pgbench stats per script & other stuff

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..eb571a8 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,18 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-B</option></term>
+      <term><option>--tpc-b</option></term>
+      <listitem>
+       <para>
+        Built-in TPC-B like test which updates three tables and performs
+        an insert on a fourth. See below for details.
+        This is the default if no bench is explicitely specified.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -313,8 +325,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
        <para>
         Read transaction script from <replaceable>filename</>.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
+        Multiple <option>-f</> options are allowed.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +415,10 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Built-in test which updates only one table compared to <option>-B</>.
+        This avoids update contention on <structname>pgbench_tellers</>
+        and <structname>pgbench_branches</>, but it makes the test case
+        even less like TPC-B.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +510,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +522,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Built-in test with select-only transactions.
        </para>
       </listitem>
      </varlistentry>
@@ -552,6 +563,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>-w</option></term>
+      <term><option>--weight</option></term>
+      <listitem>
+       <para>
+        Set the integer weight for the previous test script
+        (<option>-B</>, <option>-N</>, <option>-S</> or <option>-f</>).
+        When several test scripts are used, the relative probability of
+        drawing each test is proportional to these weights.
+        The default weight is <literal>1</>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><option>--aggregate-interval=<replaceable>seconds</></option></term>
       <listitem>
        <para>
@@ -567,6 +592,16 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>--per-script-stats</option></term>
+      <listitem>
+       <para>
+        Report some statistics per script run by pgbench.
+       </para>
+      </listitem>
+     </varlistentry>
+
+
+     <varlistentry>
       <term><option>--sampling-rate=<replaceable>rate</></option></term>
       <listitem>
        <para>
@@ -661,7 +696,17 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts (<option>-B</>, <option>-N</> and
+   <option>-S</>) and custom scripts provided by the user with <option>-f</>.
+   Each test may be given a relative weight (<option>-w</>)
+   specified <emphasis>after</> the test about which it applies so as
+   to change its draw probability.
+ </para>
+
+  <para>
+   The default transaction script (also invoked with <option>-B</>)
+   issues seven commands per transaction:
   </para>
 
   <orderedlist>
@@ -689,10 +734,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e839fa3..bbf483e 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -162,11 +162,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -186,13 +185,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL script files allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -200,22 +225,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -227,19 +250,16 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
+	int		   *exec_count;		/* number of cmd executions (per Command) */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -273,33 +293,26 @@ typedef struct
 	PgBenchExpr *expr;			/* parsed expression */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* -B case, default scenario */
+static const char *b_bench = "<builtin: TPC-B (sort of)>";
+static const char *tpc_b = {
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -317,7 +330,8 @@ static char *tpc_b = {
 };
 
 /* -N case */
-static char *simple_update = {
+static const char *n_bench = "<builtin: simple update>";
+static const char *simple_update = {
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -333,7 +347,8 @@ static char *simple_update = {
 };
 
 /* -S case */
-static char *select_only = {
+static const char *s_bench = "<builtin: select only>";
+static const char *select_only = {
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
@@ -343,8 +358,7 @@ static char *select_only = {
 static void setalarm(int seconds);
 static void *threadRun(void *arg);
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
 
 static void
 usage(void)
@@ -364,11 +378,12 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -B, --tpc-b              add TPC-B (sort-of) internal bench\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME      add transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -376,17 +391,19 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  add simple updates internal bench\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        add SELECT-only internal bench\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
+		   "  -w, --weight=NUM         set weight for previous script\n"
 		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g. 0.01 for 1%%)\n"
+		   "  --per-file-stats         report per-file statistics\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 	  "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -578,6 +595,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1097,33 +1157,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1140,7 +1188,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 	INSTR_TIME_SET_ZERO(now);
 
 top:
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1176,18 +1224,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1197,27 +1242,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1253,35 +1284,10 @@ top:
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1324,8 +1330,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1368,7 +1375,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1656,7 +1663,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1694,16 +1701,31 @@ top:
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1712,15 +1734,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1730,39 +1743,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1777,52 +1758,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1832,21 +1795,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1855,6 +1818,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2475,7 +2476,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2487,12 +2488,6 @@ process_file(char *filename)
 	char	   *buf;
 	int			alloc_num;
 
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
-
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
@@ -2503,7 +2498,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2535,13 +2530,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2595,35 +2588,54 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+static void
+addScript(const char *name, Command ** commands)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = 1;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2631,49 +2643,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2681,27 +2682,48 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
+	/* Report per-file data */
+	if (per_script_stats)
+	{
+		int i;
+
+		for (i = 0; i < num_scripts; i++)
+		{
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (tps = %f)\n",
+				   i, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt, sql_script[i].stats.cnt / time_include);
+
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
+
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+		}
+	}
+
 	/* Report per-command latencies */
 	if (is_latencies)
 	{
 		int			i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
 			Command   **commands;
 
-			if (num_files > 1)
+			if (num_scripts > 1)
 				printf("statement latencies in milliseconds, file %d:\n", i + 1);
 			else
 				printf("statement latencies in milliseconds:\n");
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
+			for (commands = sql_script[i].commands; *commands != NULL; commands++)
 			{
 				Command    *command = *commands;
 				int			cnum = command->command_num;
@@ -2739,6 +2761,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2749,12 +2772,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2762,6 +2787,7 @@ main(int argc, char **argv)
 		{"transactions", required_argument, NULL, 't'},
 		{"username", required_argument, NULL, 'U'},
 		{"vacuum-all", no_argument, NULL, 'v'},
+		{"weight", required_argument, NULL, 'w'},
 		/* long-named only options */
 		{"foreign-keys", no_argument, &foreign_keys, 1},
 		{"index-tablespace", required_argument, NULL, 3},
@@ -2769,25 +2795,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
+		{"per-script-stats", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2795,13 +2816,8 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
 
 	int			i;
 	int			nclients_dealt;
@@ -2847,7 +2863,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqBSNw:c:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2869,14 +2885,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2979,12 +2987,44 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run*/
 			case 'f':
+				addScript(optarg, process_file(optarg));
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
+				break;
+			case 'B':
+				addScript(b_bench, process_builtin(tpc_b, b_bench));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(s_bench, process_builtin(select_only, s_bench));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(n_bench, process_builtin(simple_update, n_bench));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'w':
+				{
+					int weight = atoi(optarg);
+					if (weight <= 0)
+					{
+						fprintf(stderr,
+								"invalid weight value: \"%s\"\n", optarg);
+						exit(1);
+					}
+					if (num_scripts == 0)
+					{
+						fprintf(stderr,
+								"weight must come after its script selection"
+								" (-B -N -S or -f ...)\n");
+						exit(1);
+					}
+					sql_script[num_scripts - 1].weight = weight;
+				}
 				break;
 			case 'D':
 				{
@@ -3015,7 +3055,7 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
 					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
 					exit(1);
@@ -3107,6 +3147,9 @@ main(int argc, char **argv)
 				}
 #endif
 				break;
+			case 6:
+				per_script_stats = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -3114,6 +3157,18 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(b_bench, process_builtin(tpc_b, b_bench));
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3198,8 +3253,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3242,7 +3295,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3319,31 +3372,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3359,8 +3387,8 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
 
@@ -3427,11 +3455,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3444,21 +3472,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped = threads->throttle_latency_skipped;
-		latency_late = thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
+		latency_late += thread->latency_late;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[i].txn_latencies;
-			total_sqlats += thread->state[i].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3474,10 +3494,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3498,13 +3515,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3514,8 +3525,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3552,16 +3561,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3589,7 +3599,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3602,7 +3612,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3695,7 +3705,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3726,11 +3736,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3750,23 +3756,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
-				for (i = 0; i < progress_nthreads; i++)
-					lags += thread[i].throttle_lag;
-
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
-				skipped = thread->throttle_latency_skipped - last_skipped;
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3776,16 +3783,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped", skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = thread->throttle_latency_skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..6bac511 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,18 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-B</option></term>
+      <term><option>--tpc-b</option></term>
+      <listitem>
+       <para>
+        Built-in TPC-B like test which updates three tables and performs
+        an insert on a fourth. See below for details.
+        This is the default if no bench is explicitely specified.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -313,8 +325,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
        <para>
         Read transaction script from <replaceable>filename</>.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
+        Multiple <option>-f</> options are allowed.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +415,10 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Built-in test which updates only one table compared to <option>-B</>.
+        This avoids update contention on <structname>pgbench_tellers</>
+        and <structname>pgbench_branches</>, but it makes the test case
+        even less like TPC-B.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +510,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +522,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Built-in test with select-only transactions.
        </para>
       </listitem>
      </varlistentry>
@@ -552,6 +563,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>-w</option></term>
+      <term><option>--weight</option></term>
+      <listitem>
+       <para>
+        Set the integer weight for the next test script
+        (<option>-B</>, <option>-N</>, <option>-S</> or <option>-f</>).
+        When several test scripts are used, the relative probability of
+        drawing each test is proportional to these weights.
+        The default weight is <literal>1</>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><option>--aggregate-interval=<replaceable>seconds</></option></term>
       <listitem>
        <para>
@@ -567,6 +592,16 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>--per-script-stats</option></term>
+      <listitem>
+       <para>
+        Report some statistics per script run by pgbench.
+       </para>
+      </listitem>
+     </varlistentry>
+
+
+     <varlistentry>
       <term><option>--sampling-rate=<replaceable>rate</></option></term>
       <listitem>
        <para>
@@ -661,7 +696,17 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts (<option>-B</>, <option>-N</> and
+   <option>-S</>) and custom scripts provided by the user with <option>-f</>.
+   Each test may be given a relative weight (<option>-w</>)
+   specified <emphasis>before</> the test about which it applies so as
+   to change its draw probability.
+ </para>
+
+  <para>
+   The default transaction script (also invoked with <option>-B</>)
+   issues seven commands per transaction:
   </para>
 
   <orderedlist>
@@ -689,10 +734,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e839fa3..f9d30f2 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -162,11 +162,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -186,13 +185,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL script files allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -200,22 +225,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -227,19 +250,16 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
+	int		   *exec_count;		/* number of cmd executions (per Command) */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -273,33 +293,26 @@ typedef struct
 	PgBenchExpr *expr;			/* parsed expression */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* -B case, default scenario */
+static const char *b_bench = "<builtin: TPC-B (sort of)>";
+static const char *tpc_b = {
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -317,7 +330,8 @@ static char *tpc_b = {
 };
 
 /* -N case */
-static char *simple_update = {
+static const char *n_bench = "<builtin: simple update>";
+static const char *simple_update = {
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -333,7 +347,8 @@ static char *simple_update = {
 };
 
 /* -S case */
-static char *select_only = {
+static const char *s_bench = "<builtin: select only>";
+static const char *select_only = {
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
@@ -343,8 +358,7 @@ static char *select_only = {
 static void setalarm(int seconds);
 static void *threadRun(void *arg);
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
 
 static void
 usage(void)
@@ -364,11 +378,12 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -B, --tpc-b              add TPC-B (sort-of) internal bench\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME      add transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -376,17 +391,19 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  add simple updates internal bench\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        add SELECT-only internal bench\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
+		   "  -w, --weight=NUM         set weight for next script\n"
 		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g. 0.01 for 1%%)\n"
+		   "  --per-file-stats         report per-file statistics\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 	  "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -578,6 +595,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1097,33 +1157,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1140,7 +1188,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 	INSTR_TIME_SET_ZERO(now);
 
 top:
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1176,18 +1224,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1197,27 +1242,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1253,35 +1284,10 @@ top:
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1324,8 +1330,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1368,7 +1375,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1656,7 +1663,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1694,16 +1701,31 @@ top:
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1712,15 +1734,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1730,39 +1743,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1777,52 +1758,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1832,21 +1795,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1855,6 +1818,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2475,7 +2476,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2487,12 +2488,6 @@ process_file(char *filename)
 	char	   *buf;
 	int			alloc_num;
 
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
-
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
@@ -2503,7 +2498,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2535,13 +2530,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2595,35 +2588,54 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight == 0? 1: weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2631,49 +2643,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2681,27 +2682,50 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
+	/* Report per-file data */
+	if (per_script_stats)
+	{
+		int i;
+
+		for (i = 0; i < num_scripts; i++)
+		{
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
+
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
+
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+		}
+	}
+
 	/* Report per-command latencies */
 	if (is_latencies)
 	{
 		int			i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
 			Command   **commands;
 
-			if (num_files > 1)
+			if (num_scripts > 1)
 				printf("statement latencies in milliseconds, file %d:\n", i + 1);
 			else
 				printf("statement latencies in milliseconds:\n");
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
+			for (commands = sql_script[i].commands; *commands != NULL; commands++)
 			{
 				Command    *command = *commands;
 				int			cnum = command->command_num;
@@ -2739,6 +2763,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2749,12 +2774,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2762,6 +2789,7 @@ main(int argc, char **argv)
 		{"transactions", required_argument, NULL, 't'},
 		{"username", required_argument, NULL, 'U'},
 		{"vacuum-all", no_argument, NULL, 'v'},
+		{"weight", required_argument, NULL, 'w'},
 		/* long-named only options */
 		{"foreign-keys", no_argument, &foreign_keys, 1},
 		{"index-tablespace", required_argument, NULL, 3},
@@ -2769,25 +2797,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
+		{"per-script-stats", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2795,14 +2818,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
 
+	int			weight = 0;     /* 0 means unset, will default to 1 */
 	int			i;
 	int			nclients_dealt;
 
@@ -2847,7 +2866,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqBSNw:c:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2869,14 +2888,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2979,12 +2990,42 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run*/
 			case 'f':
+				addScript(optarg, process_file(optarg), weight);
+				benchmarking_option_set = true;
+				weight = 0;
+				break;
+			case 'B':
+				addScript(b_bench, process_builtin(tpc_b, b_bench), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
+				internal_script_used = true;
+				weight = 0;
+				break;
+			case 'S':
+				addScript(s_bench, process_builtin(select_only, s_bench), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				weight = 0;
+				break;
+			case 'N':
+				addScript(n_bench, process_builtin(simple_update, n_bench), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				weight = 0;
+				break;
+			case 'w':
+				if (weight != 0)
+				{
+					fprintf(stderr, "weight set to \"%s\" but unused prior set value (%d)\n", optarg, weight);
+					exit(1);
+				}
+				weight = atoi(optarg);
+				if (weight <= 0)
+				{
+					fprintf(stderr,	"invalid weight value: \"%s\"\n", optarg);
 					exit(1);
+				}
 				break;
 			case 'D':
 				{
@@ -3015,7 +3056,7 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
 					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
 					exit(1);
@@ -3107,6 +3148,9 @@ main(int argc, char **argv)
 				}
 #endif
 				break;
+			case 6:
+				per_script_stats = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -3114,6 +3158,24 @@ main(int argc, char **argv)
 		}
 	}
 
+	if (weight != 0)
+	{
+		fprintf(stderr, "unused weight set to %d\n", weight);
+		exit (1);
+	}
+
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(b_bench, process_builtin(tpc_b, b_bench), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3198,8 +3260,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3242,7 +3302,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3319,31 +3379,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3359,8 +3394,8 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
 
@@ -3427,11 +3462,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3444,21 +3479,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped = threads->throttle_latency_skipped;
-		latency_late = thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
+		latency_late += thread->latency_late;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[i].txn_latencies;
-			total_sqlats += thread->state[i].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3474,10 +3501,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3498,13 +3522,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3514,8 +3532,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3552,16 +3568,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3589,7 +3606,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3602,7 +3619,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3695,7 +3712,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3726,11 +3743,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3750,23 +3763,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
-				for (i = 0; i < progress_nthreads; i++)
-					lags += thread[i].throttle_lag;
-
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
-				skipped = thread->throttle_latency_skipped - last_skipped;
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3776,16 +3790,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped", skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = thread->throttle_latency_skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..dc36f5d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -260,7 +260,22 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     <application>pgbench</application> accepts the following command-line
     benchmarking arguments:
 
-    <variablelist>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +322,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +420,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +512,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +524,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -567,6 +580,16 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>--per-script-stats</option></term>
+      <listitem>
+       <para>
+        Report some statistics per script run by pgbench.
+       </para>
+      </listitem>
+     </varlistentry>
+
+
+     <varlistentry>
       <term><option>--sampling-rate=<replaceable>rate</></option></term>
       <listitem>
        <para>
@@ -661,7 +684,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -675,9 +711,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -689,10 +731,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e839fa3..e8bd935 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -162,11 +162,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -177,6 +176,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -186,13 +187,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -200,22 +227,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -227,19 +252,16 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
+	int		   *exec_count;		/* number of cmd executions (per Command) */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -273,33 +295,38 @@ typedef struct
 	PgBenchExpr *expr;			/* parsed expression */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -314,10 +341,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -330,21 +357,32 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
 
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
+
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -364,11 +402,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -376,17 +416,18 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
 		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g. 0.01 for 1%%)\n"
+		   "  --per-script-stats       report per-script statistics\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 	  "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -578,6 +619,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1097,33 +1181,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1140,7 +1212,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 	INSTR_TIME_SET_ZERO(now);
 
 top:
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1176,18 +1248,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1197,27 +1266,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1253,35 +1308,10 @@ top:
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1324,8 +1354,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1368,7 +1399,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1656,7 +1687,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1694,16 +1725,31 @@ top:
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1712,15 +1758,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1730,39 +1767,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1777,52 +1782,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1832,21 +1819,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1855,6 +1842,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2475,7 +2500,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2483,15 +2508,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2503,7 +2522,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2535,13 +2554,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2595,35 +2612,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2631,49 +2690,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2681,27 +2729,50 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
+	/* Report per-file data */
+	if (per_script_stats)
+	{
+		int i;
+
+		for (i = 0; i < num_scripts; i++)
+		{
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
+
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
+
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+		}
+	}
+
 	/* Report per-command latencies */
 	if (is_latencies)
 	{
 		int			i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
 			Command   **commands;
 
-			if (num_files > 1)
+			if (num_scripts > 1)
 				printf("statement latencies in milliseconds, file %d:\n", i + 1);
 			else
 				printf("statement latencies in milliseconds:\n");
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
+			for (commands = sql_script[i].commands; *commands != NULL; commands++)
 			{
 				Command    *command = *commands;
 				int			cnum = command->command_num;
@@ -2739,6 +2810,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2749,12 +2821,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2769,25 +2843,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
+		{"per-script-stats", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2795,13 +2864,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2847,7 +2913,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2869,14 +2935,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2979,12 +3037,30 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run*/
+			case 'b':
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3015,9 +3091,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3107,6 +3183,9 @@ main(int argc, char **argv)
 				}
 #endif
 				break;
+			case 6:
+				per_script_stats = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -3114,6 +3193,19 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3198,8 +3290,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3242,7 +3332,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3319,31 +3409,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3359,8 +3424,8 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
 
@@ -3427,11 +3492,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3444,21 +3509,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped = threads->throttle_latency_skipped;
-		latency_late = thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
+		latency_late += thread->latency_late;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[i].txn_latencies;
-			total_sqlats += thread->state[i].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3474,10 +3531,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3498,13 +3552,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3514,8 +3562,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3552,16 +3598,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3589,7 +3636,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3602,7 +3649,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3695,7 +3742,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3726,11 +3773,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3750,23 +3793,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
-				for (i = 0; i < progress_nthreads; i++)
-					lags += thread[i].throttle_lag;
-
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
-				skipped = thread->throttle_latency_skipped - last_skipped;
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3776,16 +3820,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped", skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = thread->throttle_latency_skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..dc36f5d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -260,7 +260,22 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     <application>pgbench</application> accepts the following command-line
     benchmarking arguments:
 
-    <variablelist>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +322,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +420,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +512,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +524,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -567,6 +580,16 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>--per-script-stats</option></term>
+      <listitem>
+       <para>
+        Report some statistics per script run by pgbench.
+       </para>
+      </listitem>
+     </varlistentry>
+
+
+     <varlistentry>
       <term><option>--sampling-rate=<replaceable>rate</></option></term>
       <listitem>
        <para>
@@ -661,7 +684,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -675,9 +711,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -689,10 +731,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e839fa3..98a88f9 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -162,11 +162,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -177,6 +176,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -186,13 +187,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -200,22 +227,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -227,19 +252,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -271,35 +291,41 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -314,10 +340,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -330,21 +356,32 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
 
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -364,11 +401,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -376,17 +415,18 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
 		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g. 0.01 for 1%%)\n"
+		   "  --per-script-stats       report per-script statistics\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 	  "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -578,6 +618,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1097,50 +1180,41 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
 	bool		trans_needs_throttle = false;
 	instr_time	now;
 
+top:
 	/*
 	 * gettimeofday() isn't free, so we get the current timestamp lazily the
 	 * first time it's needed, and reuse the same value throughout this
 	 * function after that. This also ensures that e.g. the calculated latency
 	 * reported in the log file and in the totals are the same. Zero means
 	 * "not set yet".
+	 *
+	 * on meta command we loop over and also reset now which may be used for
+	 * per-command stats.
 	 */
 	INSTR_TIME_SET_ZERO(now);
 
-top:
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1176,18 +1250,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1197,27 +1268,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1241,47 +1298,24 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/* although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1324,8 +1358,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1368,7 +1403,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1656,7 +1691,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1688,22 +1723,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1712,15 +1764,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1730,39 +1773,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1777,52 +1788,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1832,21 +1825,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1855,6 +1848,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2251,6 +2282,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2475,7 +2507,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2483,15 +2515,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2503,7 +2529,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2535,13 +2561,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2595,35 +2619,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2631,49 +2697,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2681,53 +2736,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
 
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
+				printf(" - per command latencies in ms:\n");
 
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2739,6 +2785,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2749,12 +2796,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2769,25 +2818,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
+		{"per-script-stats", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2795,13 +2839,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2847,7 +2888,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2869,14 +2910,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2928,6 +2961,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2979,12 +3013,30 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run*/
+			case 'b':
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3015,9 +3067,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3107,6 +3159,9 @@ main(int argc, char **argv)
 				}
 #endif
 				break;
+			case 6:
+				per_script_stats = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -3114,6 +3169,19 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3198,8 +3266,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3242,7 +3308,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3319,31 +3385,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3359,32 +3400,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3427,11 +3446,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3444,21 +3463,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped = threads->throttle_latency_skipped;
-		latency_late = thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
+		latency_late += thread->latency_late;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[i].txn_latencies;
-			total_sqlats += thread->state[i].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3474,10 +3485,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3498,13 +3506,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3514,8 +3516,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3552,16 +3552,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3589,7 +3590,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3602,7 +3603,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3695,7 +3696,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3726,11 +3727,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3750,23 +3747,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
-				for (i = 0; i < progress_nthreads; i++)
-					lags += thread[i].throttle_lag;
-
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
-				skipped = thread->throttle_latency_skipped - last_skipped;
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3776,16 +3774,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped", skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = thread->throttle_latency_skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..99670d4 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,23 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +324,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +422,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +514,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +526,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -567,6 +582,16 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>--per-script-stats</option></term>
+      <listitem>
+       <para>
+        Report some statistics per script run by pgbench.
+       </para>
+      </listitem>
+     </varlistentry>
+
+
+     <varlistentry>
       <term><option>--sampling-rate=<replaceable>rate</></option></term>
       <listitem>
        <para>
@@ -661,7 +686,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -675,9 +713,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -689,10 +733,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 3b8a80f..98a88f9 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -162,11 +162,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -177,6 +176,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -186,13 +187,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -200,22 +227,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -227,19 +252,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -271,35 +291,41 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -314,10 +340,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -330,21 +356,32 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
 
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -364,11 +401,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -376,17 +415,18 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
 		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g. 0.01 for 1%%)\n"
+		   "  --per-script-stats       report per-script statistics\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 	  "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -578,6 +618,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1097,50 +1180,41 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
 	bool		trans_needs_throttle = false;
 	instr_time	now;
 
+top:
 	/*
 	 * gettimeofday() isn't free, so we get the current timestamp lazily the
 	 * first time it's needed, and reuse the same value throughout this
 	 * function after that. This also ensures that e.g. the calculated latency
 	 * reported in the log file and in the totals are the same. Zero means
 	 * "not set yet".
+	 *
+	 * on meta command we loop over and also reset now which may be used for
+	 * per-command stats.
 	 */
 	INSTR_TIME_SET_ZERO(now);
 
-top:
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1176,18 +1250,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1197,27 +1268,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1241,47 +1298,24 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/* although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1324,8 +1358,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1368,7 +1403,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1656,7 +1691,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1688,22 +1723,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1712,15 +1764,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1730,39 +1773,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1777,52 +1788,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1832,21 +1825,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1855,6 +1848,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2251,6 +2282,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2475,7 +2507,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2483,15 +2515,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2503,7 +2529,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2535,13 +2561,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2595,35 +2619,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2631,49 +2697,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2681,53 +2736,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
 
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
+				printf(" - per command latencies in ms:\n");
 
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2739,6 +2785,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2749,12 +2796,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2769,25 +2818,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
+		{"per-script-stats", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2795,13 +2839,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2847,7 +2888,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2869,14 +2910,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2928,6 +2961,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2979,12 +3013,30 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run*/
+			case 'b':
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3015,9 +3067,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3107,6 +3159,9 @@ main(int argc, char **argv)
 				}
 #endif
 				break;
+			case 6:
+				per_script_stats = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -3114,6 +3169,19 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3198,8 +3266,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3242,7 +3308,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3319,31 +3385,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3359,32 +3400,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3427,11 +3446,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3444,21 +3463,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped = threads->throttle_latency_skipped;
-		latency_late = thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
+		latency_late += thread->latency_late;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3474,10 +3485,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3498,13 +3506,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3514,8 +3516,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3552,16 +3552,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3589,7 +3590,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3602,7 +3603,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3695,7 +3696,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3726,11 +3727,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3750,23 +3747,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
-				for (i = 0; i < progress_nthreads; i++)
-					lags += thread[i].throttle_lag;
-
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
-				skipped = thread->throttle_latency_skipped - last_skipped;
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3776,16 +3774,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped", skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = thread->throttle_latency_skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..99670d4 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,23 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +324,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +422,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +514,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +526,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -567,6 +582,16 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>--per-script-stats</option></term>
+      <listitem>
+       <para>
+        Report some statistics per script run by pgbench.
+       </para>
+      </listitem>
+     </varlistentry>
+
+
+     <varlistentry>
       <term><option>--sampling-rate=<replaceable>rate</></option></term>
       <listitem>
        <para>
@@ -661,7 +686,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -675,9 +713,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -689,10 +733,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 30a59af..9954f54 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -162,11 +162,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -177,6 +176,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -186,13 +187,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -200,22 +227,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -227,19 +252,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -271,35 +291,41 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -314,10 +340,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -330,21 +356,32 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
 
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -364,11 +401,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -376,17 +415,18 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
 		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g. 0.01 for 1%%)\n"
+		   "  --per-script-stats       report per-script statistics\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 	  "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -578,6 +618,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1097,33 +1180,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
-
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1141,7 +1212,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1177,18 +1248,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1198,27 +1266,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1242,47 +1296,24 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/* although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1325,8 +1356,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1369,7 +1401,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1657,7 +1689,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1689,22 +1721,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1713,15 +1762,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1731,39 +1771,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1778,52 +1786,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1833,21 +1823,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1856,6 +1846,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2252,6 +2280,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2476,7 +2505,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2484,15 +2513,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2504,7 +2527,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2536,13 +2559,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2596,35 +2617,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2632,49 +2695,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2682,53 +2734,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
 
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
+				printf(" - per command latencies in ms:\n");
 
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2740,6 +2783,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2750,12 +2794,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2770,25 +2816,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
+		{"per-script-stats", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2796,13 +2837,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2848,7 +2886,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2870,14 +2908,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2929,6 +2959,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2980,12 +3011,30 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run*/
+			case 'b':
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3016,9 +3065,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3108,6 +3157,9 @@ main(int argc, char **argv)
 				}
 #endif
 				break;
+			case 6:
+				per_script_stats = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -3115,6 +3167,19 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3199,8 +3264,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3243,7 +3306,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3320,31 +3383,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3360,32 +3398,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3428,11 +3444,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3445,21 +3461,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped = threads->throttle_latency_skipped;
-		latency_late = thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
+		latency_late += thread->latency_late;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3475,10 +3483,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3499,13 +3504,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3515,8 +3514,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3553,16 +3550,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3590,7 +3588,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3603,7 +3601,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3696,7 +3694,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3727,11 +3725,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3751,23 +3745,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
-				for (i = 0; i < progress_nthreads; i++)
-					lags += thread[i].throttle_lag;
-
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
-				skipped = thread->throttle_latency_skipped - last_skipped;
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3777,16 +3772,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped", skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = thread->throttle_latency_skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..99670d4 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,23 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +324,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +422,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +514,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +526,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -567,6 +582,16 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
+      <term><option>--per-script-stats</option></term>
+      <listitem>
+       <para>
+        Report some statistics per script run by pgbench.
+       </para>
+      </listitem>
+     </varlistentry>
+
+
+     <varlistentry>
       <term><option>--sampling-rate=<replaceable>rate</></option></term>
       <listitem>
        <para>
@@ -661,7 +686,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -675,9 +713,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -689,10 +733,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 2e55c90..9b8e68d 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -162,11 +162,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -177,6 +176,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -186,13 +187,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -200,22 +227,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -227,19 +252,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -271,35 +291,41 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -314,10 +340,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -330,21 +356,32 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
 
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -364,11 +401,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -376,17 +415,18 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
 		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g. 0.01 for 1%%)\n"
+		   "  --per-script-stats       report per-script statistics\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 	  "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -578,6 +618,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1097,33 +1180,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
-
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1141,7 +1212,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1177,18 +1248,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1198,27 +1266,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1242,47 +1296,24 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/* although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1325,8 +1356,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1369,7 +1401,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1657,7 +1689,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1689,22 +1721,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1713,15 +1762,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1731,39 +1771,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1778,52 +1786,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1833,21 +1823,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1856,6 +1846,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2252,6 +2280,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2476,7 +2505,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2484,15 +2513,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2504,7 +2527,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2536,13 +2559,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2596,35 +2617,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2632,49 +2695,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2682,53 +2734,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
 
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
+				printf(" - per command latencies in ms:\n");
 
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2740,6 +2783,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2750,12 +2794,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2770,25 +2816,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
+		{"per-script-stats", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2796,13 +2837,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2848,7 +2886,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2870,14 +2908,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2929,6 +2959,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2980,12 +3011,30 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run*/
+			case 'b':
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3016,9 +3065,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3108,6 +3157,9 @@ main(int argc, char **argv)
 				}
 #endif
 				break;
+			case 6:
+				per_script_stats = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -3115,6 +3167,19 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3199,8 +3264,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3243,7 +3306,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3320,31 +3383,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3360,32 +3398,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3428,11 +3444,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3445,21 +3461,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3475,10 +3483,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3499,13 +3504,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3515,8 +3514,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3553,16 +3550,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3590,7 +3588,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3603,7 +3601,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3696,7 +3694,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3727,11 +3725,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3751,25 +3745,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
-				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3779,17 +3772,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 2517a3a..3edd65a 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,25 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+        With special name <literal>list</>, show the list of builtin scripts
+        and exit immediately.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +326,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +424,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -499,9 +516,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -511,7 +528,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -661,7 +678,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in pgbench?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -675,9 +705,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -689,10 +725,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 30e8d2a..8540ac7 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -164,11 +164,10 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -179,6 +178,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -188,13 +189,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
+ */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
+
+/*
  * structures used in custom query mode
  */
-
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -202,22 +229,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -229,19 +254,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -273,80 +293,97 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
-	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
-	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"\\setrandom bid 1 :nbranches\n"
-	"\\setrandom tid 1 :ntellers\n"
-	"\\setrandom delta -5000 5000\n"
-	"BEGIN;\n"
-	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-	"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
-	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
-	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
-	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
-	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"\\setrandom bid 1 :nbranches\n"
-	"\\setrandom tid 1 :ntellers\n"
-	"\\setrandom delta -5000 5000\n"
-	"BEGIN;\n"
-	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
-
 /* Function prototypes */
 static void setalarm(int seconds);
 static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
+	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
+	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
+	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+	"\\setrandom aid 1 :naccounts\n"
+	"\\setrandom bid 1 :nbranches\n"
+	"\\setrandom tid 1 :ntellers\n"
+	"\\setrandom delta -5000 5000\n"
+	"BEGIN;\n"
+	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
+	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+	"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
+	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
+	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
+	"END;\n"
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
+	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
+	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
+	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+	"\\setrandom aid 1 :naccounts\n"
+	"\\setrandom bid 1 :nbranches\n"
+	"\\setrandom tid 1 :ntellers\n"
+	"\\setrandom delta -5000 5000\n"
+	"BEGIN;\n"
+	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
+	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
+	"END;\n"
+},
+{
+	"select-only",
+	"<builtin: select only>",
+	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+	"\\setrandom aid 1 :naccounts\n"
+	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+} };
+
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
+
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -366,11 +403,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms\n"
@@ -378,12 +417,12 @@ usage(void)
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
@@ -580,6 +619,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1099,33 +1181,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1143,7 +1213,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1179,18 +1249,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1200,27 +1267,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1244,47 +1297,24 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/* although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1327,8 +1357,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1371,7 +1402,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1659,7 +1690,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1691,22 +1722,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1715,15 +1763,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1733,39 +1772,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1780,52 +1787,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1835,21 +1824,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1858,6 +1847,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2254,6 +2281,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2478,7 +2506,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2486,15 +2514,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2506,7 +2528,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2538,13 +2560,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2598,35 +2618,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2634,49 +2696,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2684,53 +2735,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i+1, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+
+			/* Report per-command latencies */
+			if (is_latencies)
 			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
+				Command ** com;
 
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+				printf(" - per command latencies in ms:\n");
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
-
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
-
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2742,6 +2784,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2752,12 +2795,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2772,25 +2817,19 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2798,13 +2837,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2850,7 +2886,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2872,14 +2908,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2931,6 +2959,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2982,12 +3011,41 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run */
+			case 'b':
+
+				if (strcmp(optarg, "list") == 0)
+				{
+					int i;
+					fprintf(stdout, "%d builtin scripts: ", N_BUILTIN);
+					for (i = 0; i < N_BUILTIN; i++)
+						fprintf(stdout, "%s ", builtin_script[i].name);
+					fprintf(stdout, "\n");
+					exit(0);
+				}
+
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3018,9 +3076,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3117,6 +3175,23 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
+	/* show per script stats if several scripts are used */
+	if (!initialization_option_set && num_scripts > 1)
+		per_script_stats = true;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3201,8 +3276,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3245,7 +3318,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3329,31 +3402,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3369,32 +3417,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3437,11 +3463,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3454,21 +3480,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3484,10 +3502,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3508,13 +3523,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3524,8 +3533,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3562,16 +3569,17 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3599,7 +3607,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3612,7 +3620,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3705,7 +3713,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
@@ -3736,11 +3744,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3760,25 +3764,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
-				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				fprintf(stderr,
 						"progress: %.1f s, %.1f tps, "
@@ -3788,17 +3791,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 0ac40f1..e3a90e5 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,25 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+        With special name <literal>list</>, show the list of builtin scripts
+        and exit immediately.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +326,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +424,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -512,9 +529,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -524,7 +541,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -674,7 +691,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -688,9 +718,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -702,10 +738,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 6ae1b86..0e56ed7 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -164,12 +164,11 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -180,6 +179,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -189,13 +190,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -203,22 +230,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -230,19 +255,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -274,35 +294,41 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -317,10 +343,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -333,21 +359,32 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
 
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -367,23 +404,25 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
@@ -581,6 +620,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1100,33 +1182,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1144,7 +1214,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1180,18 +1250,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1201,27 +1268,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1245,47 +1298,24 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/* although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1328,8 +1358,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1357,7 +1388,7 @@ top:
 			return clientDone(st, false);
 		}
 		INSTR_TIME_SET_CURRENT(end);
-		INSTR_TIME_ACCUM_DIFF(*conn_time, end, start);
+		INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	}
 
 	/*
@@ -1372,7 +1403,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1660,7 +1691,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1692,22 +1723,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1716,15 +1764,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1734,39 +1773,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1781,52 +1788,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1836,21 +1825,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1859,6 +1848,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2255,6 +2282,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2479,7 +2507,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2487,15 +2515,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2507,7 +2529,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2539,13 +2561,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2599,35 +2619,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
-						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nthreads));
-
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
+						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2635,49 +2697,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2685,53 +2736,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i+1, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
 
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
+				printf(" - per command latencies in ms:\n");
 
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2743,6 +2785,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2753,12 +2796,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2773,26 +2818,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
 		{"progress-timestamp", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2800,13 +2839,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2852,7 +2888,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2874,14 +2910,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2933,6 +2961,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2984,12 +3013,41 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run */
+			case 'b':
+
+				if (strcmp(optarg, "list") == 0)
+				{
+					int i;
+					fprintf(stdout, "%d builtin scripts: ", N_BUILTIN);
+					for (i = 0; i < N_BUILTIN; i++)
+						fprintf(stdout, "%s ", builtin_script[i].name);
+					fprintf(stdout, "\n");
+					exit(0);
+				}
+
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3020,9 +3078,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3123,6 +3181,23 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
+	/* show per script stats if several scripts are used */
+	if (!initialization_option_set && num_scripts > 1)
+		per_script_stats = true;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3207,8 +3282,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3251,7 +3324,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3335,31 +3408,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3375,32 +3423,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3443,11 +3469,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3460,21 +3486,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3490,10 +3508,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3514,13 +3529,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3530,8 +3539,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3568,17 +3575,18 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
-		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
+		if (!doCustom(thread, st, logfile, &aggs))
 			remains--;			/* I've aborted */
 
 		if (st->ecnt > prev_ecnt && commands[st->state]->type == META_COMMAND)
@@ -3605,7 +3613,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3618,7 +3626,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3711,13 +3719,13 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
 							|| commands[st->state]->type == META_COMMAND))
 			{
-				if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+				if (!doCustom(thread, st, logfile, &aggs))
 					remains--;	/* I've aborted */
 			}
 
@@ -3742,11 +3750,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3767,25 +3771,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
-				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				if (progress_timestamp)
 					sprintf(tbuf, "%.03f s",
@@ -3801,17 +3804,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 0ac40f1..e3a90e5 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,25 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <repleacable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+        With special name <literal>list</>, show the list of builtin scripts
+        and exit immediately.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +326,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +424,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -512,9 +529,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -524,7 +541,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -674,7 +691,20 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -688,9 +718,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -702,10 +738,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index f2d435b..0e56ed7 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -164,12 +164,11 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -180,6 +179,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -189,13 +190,39 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64_t count;    /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/* data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
+ */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
+
+/*
  * structures used in custom query mode
  */
-
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -203,22 +230,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -230,19 +255,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -274,80 +294,97 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+	const char *name;
+	int weight;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
+
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
-	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
-	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"\\setrandom bid 1 :nbranches\n"
-	"\\setrandom tid 1 :ntellers\n"
-	"\\setrandom delta -5000 5000\n"
-	"BEGIN;\n"
-	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-	"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
-	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
-	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
-	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
-	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"\\setrandom bid 1 :nbranches\n"
-	"\\setrandom tid 1 :ntellers\n"
-	"\\setrandom delta -5000 5000\n"
-	"BEGIN;\n"
-	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
-
 /* Function prototypes */
 static void setalarm(int seconds);
 static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
+	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
+	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
+	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+	"\\setrandom aid 1 :naccounts\n"
+	"\\setrandom bid 1 :nbranches\n"
+	"\\setrandom tid 1 :ntellers\n"
+	"\\setrandom delta -5000 5000\n"
+	"BEGIN;\n"
+	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
+	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+	"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
+	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
+	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
+	"END;\n"
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
+	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
+	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
+	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+	"\\setrandom aid 1 :naccounts\n"
+	"\\setrandom bid 1 :nbranches\n"
+	"\\setrandom tid 1 :ntellers\n"
+	"\\setrandom delta -5000 5000\n"
+	"BEGIN;\n"
+	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
+	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
+	"END;\n"
+},
+{
+	"select-only",
+	"<builtin: select only>",
+	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+	"\\setrandom aid 1 :naccounts\n"
+	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+} };
+
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
+
+	fprintf(stderr, "no builtin found for \"%s\"\n", name);
+	exit(1);
+}
 
 static void
 usage(void)
@@ -367,23 +404,25 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
@@ -581,6 +620,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1100,33 +1182,21 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
 
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
 
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1144,7 +1214,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1180,18 +1250,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1201,27 +1268,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1245,47 +1298,24 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/* although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1328,8 +1358,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1357,7 +1388,7 @@ top:
 			return clientDone(st, false);
 		}
 		INSTR_TIME_SET_CURRENT(end);
-		INSTR_TIME_ACCUM_DIFF(*conn_time, end, start);
+		INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	}
 
 	/*
@@ -1372,7 +1403,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1660,7 +1691,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1692,22 +1723,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1716,15 +1764,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1734,39 +1773,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1781,52 +1788,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1836,21 +1825,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1859,6 +1848,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2255,6 +2282,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2479,7 +2507,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2487,15 +2515,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2507,7 +2529,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2539,13 +2561,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2599,35 +2619,77 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		*sep++ = '\0';
+		weight = atoi(sep);
+		if (weight <= 0)
+		{
+			fprintf(stderr,
+					"weight must be strictly positive, got \"%s\"\n", sep);
+			exit(1);
+		}
+	}
+	else
+		weight = 1;
+	return weight;
+}
+
+static void
+addScript(const char *name, Command ** commands, int weight)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2635,49 +2697,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2685,53 +2736,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d, weight %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i+1, sql_script[i].weight, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+
+			/* Report per-command latencies */
+			if (is_latencies)
 			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
+				Command ** com;
 
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+				printf(" - per command latencies in ms:\n");
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
-
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
-
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2743,6 +2785,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'B'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2753,12 +2796,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2773,26 +2818,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
 		{"progress-timestamp", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2800,13 +2839,10 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	int			weight;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2852,7 +2888,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2874,14 +2910,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2933,6 +2961,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2984,12 +3013,41 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run */
+			case 'b':
+
+				if (strcmp(optarg, "list") == 0)
+				{
+					int i;
+					fprintf(stdout, "%d builtin scripts: ", N_BUILTIN);
+					for (i = 0; i < N_BUILTIN; i++)
+						fprintf(stdout, "%s ", builtin_script[i].name);
+					fprintf(stdout, "\n");
+					exit(0);
+				}
+
+				weight = getWeight(optarg);
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc), weight);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc), 1);
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3020,9 +3078,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3123,6 +3181,23 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !initialization_option_set)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc), 1);
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
+	/* show per script stats if several scripts are used */
+	if (!initialization_option_set && num_scripts > 1)
+		per_script_stats = true;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3207,8 +3282,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3251,7 +3324,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3335,31 +3408,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3375,32 +3423,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3443,11 +3469,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3460,21 +3486,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3490,10 +3508,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3514,13 +3529,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3530,8 +3539,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3568,17 +3575,18 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
-		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
+		if (!doCustom(thread, st, logfile, &aggs))
 			remains--;			/* I've aborted */
 
 		if (st->ecnt > prev_ecnt && commands[st->state]->type == META_COMMAND)
@@ -3605,7 +3613,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3618,7 +3626,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3711,13 +3719,13 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
 							|| commands[st->state]->type == META_COMMAND))
 			{
-				if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+				if (!doCustom(thread, st, logfile, &aggs))
 					remains--;	/* I've aborted */
 			}
 
@@ -3742,11 +3750,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3767,25 +3771,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
-				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				if (progress_timestamp)
 					sprintf(tbuf, "%.03f s",
@@ -3801,17 +3804,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 0ac40f1..62ce496 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,23 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname</></term>
+      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+        With special name <literal>list</>, show the list of builtin scripts
+        and exit immediately.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +324,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename</></term>
+      <term><option>--file=</><replaceable>filename</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +420,8 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Run builtin simple-update script.
+        Shorthand for <option>-b simple-update</>.
        </para>
       </listitem>
      </varlistentry>
@@ -512,9 +526,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -524,7 +538,8 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Run built-in select-only script.
+        Shorthand for <option>-b select-only</>.
        </para>
       </listitem>
      </varlistentry>
@@ -674,7 +689,17 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -688,9 +713,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -702,10 +733,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index f2d435b..1e0c7cc 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -164,12 +164,11 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -189,13 +188,40 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64 count;  /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/*
+ * data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
  */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
 
+/*
+ * structures used in custom query mode
+ */
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -203,22 +229,20 @@ typedef struct
 	int			state;			/* state No. */
 	int			listen;			/* 0 indicates that an async query has been
 								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -230,19 +254,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -274,35 +293,39 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
 typedef struct
 {
+	const char *name;
+	Command **commands;
+	StatsData stats;
+} SQLScript;
 
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -317,10 +340,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -333,21 +356,35 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
 
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
+
+	fprintf(stderr, "no builtin found for \"%s\" (available choices:", name);
+	for (i = 0; i < N_BUILTIN; i++)
+		fprintf(stderr, " \"%s\"", builtin_script[i].name);
+	fprintf(stderr, ")\n");
+	exit(1);
+}
 
 static void
 usage(void)
@@ -367,23 +404,27 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME       add buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME      add transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches,\n"
+		   "                           same as \"-b simple-update@1\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        perform SELECT-only transactions,\n"
+		   "                           same as \"-b select-only@1\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
@@ -581,6 +622,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1100,33 +1184,15 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
+static int
+chooseScript(TState *thread)
 {
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
-
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
+	return getrand(thread, 0, num_scripts - 1);
 }
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1144,7 +1210,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1180,18 +1246,15 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1201,27 +1264,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = false;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1245,47 +1294,25 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/*
+			 * although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1328,8 +1355,9 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -1357,7 +1385,7 @@ top:
 			return clientDone(st, false);
 		}
 		INSTR_TIME_SET_CURRENT(end);
-		INSTR_TIME_ACCUM_DIFF(*conn_time, end, start);
+		INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	}
 
 	/*
@@ -1372,7 +1400,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1660,7 +1688,7 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
 			st->listen = 1;
 		}
@@ -1692,22 +1720,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1716,15 +1761,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1734,39 +1770,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1781,52 +1785,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1836,21 +1822,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1859,6 +1845,44 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2255,6 +2279,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2479,7 +2504,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2487,15 +2512,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2507,7 +2526,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2539,13 +2558,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2599,35 +2616,53 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+static void
+addScript(const char *name, Command ** commands)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
+	num_scripts++;
+}
+
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2635,49 +2670,38 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2685,53 +2709,44 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-file data */
+	if (per_script_stats)
 	{
-		int			i;
+		int i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i+1, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
 
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
 
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
+				printf(" - per command latencies in ms:\n");
 
-				printf("\t%f\t%s\n", total_time, command->line);
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
 			}
 		}
 	}
@@ -2743,6 +2758,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'b'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2753,12 +2769,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2773,26 +2791,20 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
 		{"progress-timestamp", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2800,13 +2812,9 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2852,7 +2860,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2874,14 +2882,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2933,6 +2933,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -2984,12 +2985,39 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run */
+			case 'b':
+
+				if (strcmp(optarg, "list") == 0)
+				{
+					int i;
+					fprintf(stdout, "%d builtin scripts: ", N_BUILTIN);
+					for (i = 0; i < N_BUILTIN; i++)
+						fprintf(stdout, "%s ", builtin_script[i].name);
+					fprintf(stdout, "\n");
+					exit(0);
+				}
+
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				addScript(optarg, process_file(optarg));
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3020,9 +3048,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3123,6 +3151,19 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !is_init_mode)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc));
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
+	/* show per script stats if several scripts are used */
+	if (num_scripts > 1)
+		per_script_stats = true;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3207,8 +3248,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3251,7 +3290,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3335,31 +3374,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3375,32 +3389,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3443,11 +3435,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3460,21 +3452,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3490,10 +3474,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3514,13 +3495,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3530,8 +3505,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3568,17 +3541,18 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
-		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
+		if (!doCustom(thread, st, logfile, &aggs))
 			remains--;			/* I've aborted */
 
 		if (st->ecnt > prev_ecnt && commands[st->state]->type == META_COMMAND)
@@ -3605,7 +3579,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3618,7 +3592,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;
@@ -3711,13 +3685,13 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
 							|| commands[st->state]->type == META_COMMAND))
 			{
-				if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+				if (!doCustom(thread, st, logfile, &aggs))
 					remains--;	/* I've aborted */
 			}
 
@@ -3742,11 +3716,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3767,25 +3737,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
-				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				if (progress_timestamp)
 					sprintf(tbuf, "%.03f s",
@@ -3801,17 +3770,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 21182a7..ea0aa40 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         The provided <replaceable>scriptname</> needs only to be a prefix
@@ -324,12 +326,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -421,7 +425,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <listitem>
        <para>
         Run builtin simple-update script.
-        Shorthand for <option>-b simple-update</>.
+        Shorthand for <option>-b simple-update@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -539,7 +543,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <listitem>
        <para>
         Run built-in select-only script.
-        Shorthand for <option>-b select-only</>.
+        Shorthand for <option>-b select-only@1</>.
        </para>
       </listitem>
      </varlistentry>
@@ -692,6 +696,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    Pgbench executes test scripts chosen randomly from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index b75cd80..cd2c0f3 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -179,6 +179,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -301,6 +303,7 @@ typedef struct
 typedef struct
 {
 	const char *name;
+	int weight;
 	Command **commands;
 	StatsData stats;
 } SQLScript;
@@ -308,6 +311,7 @@ typedef struct
 static SQLScript sql_script[MAX_SCRIPTS];
 static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
 
 static int	debug = 0;			/* debug flag */
 
@@ -404,13 +408,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
-		   "  -b, --builtin=NAME       add buitin script among \"tpcb-like\"\n"
+		   "  -b, --builtin=NAME@W     add weighted buitin script among \"tpcb-like\"\n"
 		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME@W    add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
@@ -1187,7 +1191,13 @@ clientDone(CState *st, bool ok)
 static int
 chooseScript(TState *thread)
 {
-	return getrand(thread, 0, num_scripts - 1);
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
+
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2616,8 +2626,41 @@ process_builtin(const char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		char *s;
+		*sep++ = '\0';
+
+		/* check that the weight is a positive integer */
+		s = sep;
+		while ('0' <= *s && *s <= '9')
+			s++;
+		if (*s != '\0' || s == sep)
+		{
+			/* empty or any other char */
+			fprintf(stderr,
+					"weight for script \"%s\" must be an integer, got \"%s\"\n",
+					option, sep);
+			exit(1);
+		}
+
+		weight = atoi(sep);
+	}
+	else
+		weight = 1;
+
+	return weight;
+}
+
 static void
-addScript(const char *name, Command ** commands)
+addScript(const char *name, Command ** commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2632,6 +2675,7 @@ addScript(const char *name, Command ** commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(& sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2721,9 +2765,9 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
+			printf("SQL script %d, weight %d: %s\n"
 				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
-				   i+1, sql_script[i].name,
+				   i+1, sql_script[i].weight, sql_script[i].name,
 				   sql_script[i].stats.cnt,
 				   100.0 * sql_script[i].stats.cnt / total->cnt,
 				   sql_script[i].stats.cnt / time_include);
@@ -2814,6 +2858,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
+	int			weight;
 	char	   *desc;
 
 	int			i;
@@ -2998,25 +3043,27 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
+				weight = getWeight(optarg);
 				addScript(desc, process_builtin(
-							  find_builtin(optarg, &desc), desc));
+							  find_builtin(optarg, &desc), desc), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'S':
 				addScript(desc, process_builtin(
-							  find_builtin("select-only", &desc), desc));
+							  find_builtin("select-only", &desc), desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc, process_builtin(
-							  find_builtin("simple-update", &desc), desc));
+							  find_builtin("simple-update", &desc), desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3155,11 +3202,15 @@ main(int argc, char **argv)
 	if (num_scripts == 0 && !is_init_mode)
 	{
 		addScript(desc, process_builtin(
-					  find_builtin("tpcb-like", &desc), desc));
+					  find_builtin("tpcb-like", &desc), desc), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (!initialization_option_set && num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 541d17b..fdd3331 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,23 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname</></term>
+      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+        With special name <literal>list</>, show the list of builtin scripts
+        and exit immediately.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +324,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename</></term>
+      <term><option>--file=</><replaceable>filename</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +420,8 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Run builtin simple-update script.
+        Shorthand for <option>-b simple-update</>.
        </para>
       </listitem>
      </varlistentry>
@@ -512,9 +526,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -524,7 +538,8 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Run built-in select-only script.
+        Shorthand for <option>-b select-only</>.
        </para>
       </listitem>
      </varlistentry>
@@ -674,7 +689,17 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -688,9 +713,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -702,10 +733,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
@@ -1112,7 +1140,8 @@ number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-statement latencies in milliseconds:
+SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
+ - per command latencies in ms:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
         0.001212        \set naccounts 100000 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 9e422c5..3409659 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -189,7 +189,7 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
@@ -211,8 +211,8 @@ typedef struct
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
 	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
 	int			cnt;			/* xacts count */
@@ -276,6 +276,14 @@ typedef struct
 	PgBenchExpr *expr;			/* parsed expression */
 } Command;
 
+/* SQL script to be executed, either a file or an internal script
+ */
+typedef struct
+{
+	const char *name;
+	Command   **commands;
+} SQLScript;
+
 typedef struct
 {
 
@@ -296,13 +304,21 @@ typedef struct
 	double		sum2_lag;		/* sum(lag*lag) */
 } AggVals;
 
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+static SQLScript sql_script[MAX_SCRIPTS];	/* SQL script files */
+static int	num_scripts;			/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct {
+	char *name;   /* very short name for -b ...*/
+	char *desc;   /* short description */
+	char *script; /* actual pgbench script */
+} builtin_script[] = {
+{
+	"tpcb-like",
+	"<builtin: TPC-B (sort of)>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -317,10 +333,10 @@ static char *tpc_b = {
 	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -N case */
-static char *simple_update = {
+},
+{
+	"simple-update",
+	"<builtin: simple update>",
 	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
 	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
@@ -333,14 +349,35 @@ static char *simple_update = {
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
 	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
+},
+{
+	"select-only",
+	"<builtin: select only>",
 	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 	"\\setrandom aid 1 :naccounts\n"
 	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
+} };
+
+static char *
+find_builtin(const char *name, char **desc)
+{
+	int		len = strlen(name), i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].script;
+		}
+	}
+	fprintf(stderr, "no builtin found for \"%s\" (available choices:", name);
+	for (i = 0; i < N_BUILTIN; i++)
+		fprintf(stderr, " \"%s\"", builtin_script[i].name);
+	fprintf(stderr, ")\n");
+	exit(1);
+}
+
 
 /* Function prototypes */
 static void setalarm(int seconds);
@@ -367,23 +404,28 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
+		   "  -b, --builtin=NAME       add buitin script among \"tpcb-like\"\n"
+		   "                           \"simple-update\" and \"select-only\".\n"
+
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME      add transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches,\n"
+		   "                           same as \"-b simple-update\"\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "  -S, --select-only        perform SELECT-only transactions,\n"
+		   "                           same as \"-b select-only\"\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
@@ -1124,6 +1166,12 @@ agg_vals_init(AggVals *aggs, instr_time start)
 	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
 }
 
+static int
+chooseScript(TState *thread)
+{
+	return getrand(thread, 0, num_scripts - 1);
+}
+
 /* return false iff client should be disconnected */
 static bool
 doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
@@ -1144,7 +1192,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1328,8 +1376,8 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = num_scripts==1? 0: chooseScript(thread);
+			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
 			/*
@@ -2488,7 +2536,7 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2496,15 +2544,9 @@ process_file(char *filename)
 	Command   **my_commands;
 	FILE	   *fd;
 	int			lineno,
-				index;
+				index,
+				alloc_num;
 	char	   *buf;
-	int			alloc_num;
-
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
@@ -2516,7 +2558,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2548,13 +2590,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2608,9 +2648,29 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+static void
+addScript(const char *name, Command ** commands)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty commands for %s\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].commands = commands;
+	num_scripts++;
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
+printResults(int64 normal_xacts, int nclients,
 			 TState *threads, int nthreads,
 			 instr_time total_time, instr_time conn_total_time,
 			 int64 total_latencies, int64 total_sqlats,
@@ -2620,23 +2680,14 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
 	tps_include = normal_xacts / time_include;
 	tps_exclude = normal_xacts / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1? sql_script[0].name: "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2705,16 +2756,14 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	{
 		int			i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
 			Command   **commands;
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			printf("SQL script %d: %s\n", i+1, sql_script[i].name);
+			printf(" - per command latencies in ms:\n");
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
+			for (commands = sql_script[i].commands; *commands != NULL; commands++)
 			{
 				Command    *command = *commands;
 				int			cnum = command->command_num;
@@ -2752,6 +2801,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'b'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2794,14 +2844,12 @@ main(int argc, char **argv)
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2816,6 +2864,7 @@ main(int argc, char **argv)
 	int64		throttle_lag_max = 0;
 	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2861,7 +2910,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2883,14 +2932,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2993,12 +3034,39 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
+				/* what to run */
+			case 'b':
+
+				if (strcmp(optarg, "list") == 0)
+				{
+					int i;
+					fprintf(stdout, "%d builtin scripts: ", N_BUILTIN);
+					for (i = 0; i < N_BUILTIN; i++)
+						fprintf(stdout, "%s ", builtin_script[i].name);
+					fprintf(stdout, "\n");
+					exit(0);
+				}
+
+				addScript(desc, process_builtin(
+							  find_builtin(optarg, &desc), desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc, process_builtin(
+							  find_builtin("select-only", &desc), desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc, process_builtin(
+							  find_builtin("simple-update", &desc), desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
 			case 'f':
+				addScript(optarg, process_file(optarg));
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3029,9 +3097,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3132,6 +3200,15 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !is_init_mode)
+	{
+		addScript(desc, process_builtin(
+					  find_builtin("tpcb-like", &desc), desc));
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3260,7 +3337,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3344,31 +3421,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3499,7 +3551,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
+	printResults(total_xacts, nclients, threads, nthreads,
 				 total_time, conn_total_time, total_latencies, total_sqlats,
 				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
 				 latency_late);
@@ -3583,10 +3635,10 @@ threadRun(void *arg)
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
+		Command   **commands = sql_script[st->use_file].commands;
 		int			prev_ecnt = st->ecnt;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = num_scripts==1? 0: chooseScript(thread);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3614,7 +3666,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3720,7 +3772,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 3409659..f7b84da 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -166,10 +166,8 @@ int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;	    /* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -193,9 +191,36 @@ typedef struct
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
+ * simple data structure to keep stats about something.
+ * probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64 count;  /* how many values where encountered */
+	double min;   /* the minimum seen */
+	double max;   /* the maximum seen */
+	double sum;   /* sum of values */
+	double sum2;  /* sum of squared values */
+} SimpleStats;
+
+/*
+ * data structure to hold various statistics.
+ * it is used for interval statistics as well as file statistics.
+ */
+typedef struct
+{
+	long		start_time;		/* when the interval starts, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats	latency;
+	SimpleStats	lag;
+} StatsData;
+
+/*
  * structures used in custom query mode
  */
-
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -215,10 +240,8 @@ typedef struct
 	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -230,19 +253,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
-	unsigned short random_state[3];		/* separate randomness for each thread */
-	int64		throttle_trigger;		/* previous/next throttling (us) */
+	unsigned short random_state[3];	 /* separate randomness for each thread */
+	int64		throttle_trigger;	 /* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData   stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -274,6 +292,7 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats	stats;          /* time spent in this command */
 } Command;
 
 /* SQL script to be executed, either a file or an internal script
@@ -281,34 +300,20 @@ typedef struct
 typedef struct
 {
 	const char *name;
-	Command   **commands;
+	Command **commands;
 } SQLScript;
 
-typedef struct
-{
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
-static SQLScript sql_script[MAX_SCRIPTS];	/* SQL script files */
-static int	num_scripts;			/* number of scripts in sql_script[] */
+static SQLScript sql_script[MAX_SCRIPTS];
+static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+
 static int	debug = 0;			/* debug flag */
 
+/* Function prototypes */
+static void setalarm(int seconds);
+static void *threadRun(void *arg);
+static void doTxStats(TState*, CState*, instr_time*, bool, FILE*, StatsData*);
+
 /* Define builtin test scripts */
 #define N_BUILTIN 3
 static struct {
@@ -371,6 +376,7 @@ find_builtin(const char *name, char **desc)
 			return builtin_script[i].script;
 		}
 	}
+
 	fprintf(stderr, "no builtin found for \"%s\" (available choices:", name);
 	for (i = 0; i < N_BUILTIN; i++)
 		fprintf(stderr, " \"%s\"", builtin_script[i].name);
@@ -378,14 +384,6 @@ find_builtin(const char *name, char **desc)
 	exit(1);
 }
 
-
-/* Function prototypes */
-static void setalarm(int seconds);
-static void *threadRun(void *arg);
-
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
-
 static void
 usage(void)
 {
@@ -406,7 +404,6 @@ usage(void)
 		   "\nBenchmarking options:\n"
 		   "  -b, --builtin=NAME       add buitin script among \"tpcb-like\"\n"
 		   "                           \"simple-update\" and \"select-only\".\n"
-
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
@@ -623,6 +620,49 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+static void
+initSimpleStats(SimpleStats * ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+static void
+doSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count ++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+static void
+appendSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(& sd->latency);
+	initSimpleStats(& sd->lag);
+
+	/* not necessarily overriden? */
+	if (start_time)
+		sd->start_time = start_time;
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1142,30 +1182,6 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
-{
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
-
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
-}
-
 static int
 chooseScript(TState *thread)
 {
@@ -1174,7 +1190,7 @@ chooseScript(TState *thread)
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1228,11 +1244,8 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st,  &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
@@ -1249,27 +1262,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			st->sleeping = 0;	/* Done sleeping, go ahead with next command */
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = 0;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1293,47 +1292,25 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/*
+			 * although a mutex would make sense, the likelyhood of an issue
+			 * is small and these are only stats which may be slightly false
+			 */
+			doSimpleStats(& commands[st->state]->stats,
+						  INSTR_TIME_GET_DOUBLE(now) -
+						  INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt ++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1377,6 +1354,7 @@ top:
 		{
 			st->state = 0;
 			st->use_file = num_scripts==1? 0: chooseScript(thread);
+
 			commands = sql_script[st->use_file].commands;
 			st->is_throttled = false;
 
@@ -1405,7 +1383,7 @@ top:
 			return clientDone(st, false);
 		}
 		INSTR_TIME_SET_CURRENT(end);
-		INSTR_TIME_ACCUM_DIFF(*conn_time, end, start);
+		INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	}
 
 	/*
@@ -1748,22 +1726,39 @@ top:
 			else	/* succeeded */
 				st->listen = 1;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt ++;
+
+	if (skipped)
+		/* no latency to record on skipped transactions */
+		stats->skipped ++;
+	else
+	{
+		doSimpleStats(& stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			doSimpleStats(& stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1772,15 +1767,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1790,39 +1776,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1837,52 +1791,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1892,21 +1828,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d "INT64_FORMAT" %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1915,6 +1851,41 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double latency = 0.0, lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(& thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt ++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2311,6 +2282,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(& my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2668,22 +2640,28 @@ addScript(const char *name, Command ** commands)
 	num_scripts++;
 }
 
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double latency = ss->sum / ss->count;
+	double stddev = sqrt(ss->sum2 / ss->count - latency*latency);
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
 	printf("transaction type: %s\n",
@@ -2695,49 +2673,38 @@ printResults(int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: "INT64_FORMAT"/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
-		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+		printf("number of transactions actually processed: "INT64_FORMAT"\n",
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
-		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+		printf("number of transactions skipped: "INT64_FORMAT" (%.3f %%)\n",
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+		   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", & total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
-	{
 		/*
 		 * Report average transaction lag under rate limit throttling.  This
 		 * is the delay between scheduled and actual start times for the
@@ -2745,8 +2712,7 @@ printResults(int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
-	}
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
@@ -2758,39 +2724,14 @@ printResults(int64 normal_xacts, int nclients,
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			Command ** com;
 
 			printf("SQL script %d: %s\n", i+1, sql_script[i].name);
 			printf(" - per command latencies in ms:\n");
-
-			for (commands = sql_script[i].commands; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
-
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
-
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
-
-				printf("\t%f\t%s\n", total_time, command->line);
-			}
+			for (com = sql_script[i].commands; *com != NULL; com++)
+				printf("   %11.3f  %s\n",
+					   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+					   (*com)->line);
 		}
 	}
 }
@@ -2839,8 +2780,6 @@ main(int argc, char **argv)
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
@@ -2857,13 +2796,8 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
 	char	   *desc;
 
 	int			i;
@@ -3293,8 +3227,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3436,32 +3368,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(& thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3504,11 +3414,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(& stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3521,21 +3431,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		appendSimpleStats(& stats.latency, & thread->stats.latency);
+		appendSimpleStats(& stats.lag, & thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3551,10 +3453,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3575,13 +3474,7 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last, aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3591,8 +3484,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3629,7 +3520,8 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
@@ -3639,7 +3531,7 @@ threadRun(void *arg)
 		int			prev_ecnt = st->ecnt;
 
 		st->use_file = num_scripts==1? 0: chooseScript(thread);
-		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+		if (!doCustom(thread, st, logfile, &aggs))
 			remains--;			/* I've aborted */
 
 		if (st->ecnt > prev_ecnt && commands[st->state]->type == META_COMMAND)
@@ -3778,7 +3670,7 @@ threadRun(void *arg)
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
 							|| commands[st->state]->type == META_COMMAND))
 			{
-				if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+				if (!doCustom(thread, st, logfile, &aggs))
 					remains--;	/* I've aborted */
 			}
 
@@ -3803,11 +3695,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData   cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3828,25 +3716,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(& cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
-				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					appendSimpleStats(& cur.latency, & thread[i].stats.latency);
+					appendSimpleStats(& cur.lag, & thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				if (progress_timestamp)
 					sprintf(tbuf, "%.03f s",
@@ -3862,17 +3749,13 @@ threadRun(void *arg)
 				{
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
-						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+						fprintf(stderr, ", "INT64_FORMAT" skipped",
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index fdd3331..a0fe766 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1141,6 +1141,9 @@ number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
 SQL script 1: <builtin: TPC-B (sort of)>
+ - 10000 transactions (100.0% of total, tps = 618.764555)
+ - latency average = 15.844 ms
+ - latency stddev = 2.715 ms
  - per command latencies in ms:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index f7b84da..b20d00c 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -164,6 +164,7 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
 int			nclients = 1;		/* number of clients */
@@ -301,6 +302,7 @@ typedef struct
 {
 	const char *name;
 	Command **commands;
+	StatsData stats;
 } SQLScript;
 
 static SQLScript sql_script[MAX_SCRIPTS];
@@ -1307,7 +1309,7 @@ top:
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			if (progress || throttle_delay || latency_limit || logfile)
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
 				doTxStats(thread, st, &now, false, logfile, agg);
 			else
 				thread->stats.cnt ++;
@@ -1398,7 +1400,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1883,6 +1885,9 @@ doTxStats(TState *thread, CState *st, instr_time *now,
 
 	if (use_log)
 		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
 }
 
 
@@ -2637,6 +2642,7 @@ addScript(const char *name, Command ** commands)
 
 	sql_script[num_scripts].name = name;
 	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
 
@@ -2717,21 +2723,40 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-script stats */
+	if (per_script_stats)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			Command ** com;
-
-			printf("SQL script %d: %s\n", i+1, sql_script[i].name);
-			printf(" - per command latencies in ms:\n");
-			for (com = sql_script[i].commands; *com != NULL; com++)
-				printf("   %11.3f  %s\n",
-					   1000.0 * (*com)->stats.sum / (*com)->stats.count,
-					   (*com)->line);
+			printf("SQL script %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i+1, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
+
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
+
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
+
+				printf(" - per command latencies in ms:\n");
+
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
+			}
 		}
 	}
 }
@@ -2917,6 +2942,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -3143,6 +3169,10 @@ main(int argc, char **argv)
 		internal_script_used = true;
 	}
 
+	/* show per script stats if several scripts are used */
+	if (num_scripts > 1)
+		per_script_stats = true;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index a0fe766..86d3c59 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         The provided <replaceable>scriptname</> needs only to be a prefix
@@ -324,12 +326,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -692,6 +696,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    Pgbench executes test scripts chosen randomly from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1140,7 +1147,7 @@ number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
+SQL script 1, weight 1: &lt;builtin: TPC-B (sort of)&gt;
  - 10000 transactions (100.0% of total, tps = 618.764555)
  - latency average = 15.844 ms
  - latency stddev = 2.715 ms
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index b20d00c..23256fb 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -179,6 +179,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -301,6 +303,7 @@ typedef struct
 typedef struct
 {
 	const char *name;
+	int weight;
 	Command **commands;
 	StatsData stats;
 } SQLScript;
@@ -308,6 +311,7 @@ typedef struct
 static SQLScript sql_script[MAX_SCRIPTS];
 static int	num_scripts;		/* number of script in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
 
 static int	debug = 0;			/* debug flag */
 
@@ -404,13 +408,13 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nBenchmarking options:\n"
-		   "  -b, --builtin=NAME       add buitin script among \"tpcb-like\"\n"
+		   "  -b, --builtin=NAME[@W]   add weighted buitin script among \"tpcb-like\"\n"
 		   "                           \"simple-update\" and \"select-only\".\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		 "  -f, --file=FILENAME[@W]  add weighted transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
@@ -1187,7 +1191,13 @@ clientDone(CState *st, bool ok)
 static int
 chooseScript(TState *thread)
 {
-	return getrand(thread, 0, num_scripts - 1);
+	int i = 0, w = 0, wc = (int) getrand(thread, 0, total_weight - 1);
+
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2625,8 +2635,41 @@ process_builtin(const char *tb, const char *source)
 	return my_commands;
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		char *s;
+		*sep++ = '\0';
+
+		/* check that the weight is a positive integer */
+		s = sep;
+		while ('0' <= *s && *s <= '9')
+			s++;
+		if (*s != '\0' || s == sep)
+		{
+			/* empty or any other char */
+			fprintf(stderr,
+					"weight for script \"%s\" must be an integer, got \"%s\"\n",
+					option, sep);
+			exit(1);
+		}
+
+		weight = atoi(sep);
+	}
+	else
+		weight = 1;
+
+	return weight;
+}
+
 static void
-addScript(const char *name, Command ** commands)
+addScript(const char *name, Command ** commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2641,6 +2684,7 @@ addScript(const char *name, Command ** commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(& sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2723,16 +2767,16 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-script stats */
+	/* Report per-file data */
 	if (per_script_stats)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
+			printf("SQL script %d, weight %d: %s\n"
 				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
-				   i+1, sql_script[i].name,
+				   i+1, sql_script[i].weight, sql_script[i].name,
 				   sql_script[i].stats.cnt,
 				   100.0 * sql_script[i].stats.cnt / total->cnt,
 				   sql_script[i].stats.cnt / time_include);
@@ -2823,6 +2867,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
+	int			weight;
 	char	   *desc;
 
 	int			i;
@@ -3007,25 +3052,27 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
+				weight = getWeight(optarg);
 				addScript(desc, process_builtin(
-							  find_builtin(optarg, &desc), desc));
+							  find_builtin(optarg, &desc), desc), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'S':
 				addScript(desc, process_builtin(
-							  find_builtin("select-only", &desc), desc));
+							  find_builtin("select-only", &desc), desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc, process_builtin(
-							  find_builtin("simple-update", &desc), desc));
+							  find_builtin("simple-update", &desc), desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3164,11 +3211,15 @@ main(int argc, char **argv)
 	if (num_scripts == 0 && !is_init_mode)
 	{
 		addScript(desc, process_builtin(
-					  find_builtin("tpcb-like", &desc), desc));
+					  find_builtin("tpcb-like", &desc), desc), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 23256fb..0b2a2f9 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -229,16 +229,15 @@ typedef struct
 	PGconn	   *con;			/* connection handle to DB */
 	int			id;				/* client No. */
 	int			state;			/* state No. */
-	int			listen;			/* 0 indicates that an async query has been
-								 * sent */
-	int			sleeping;		/* 1 indicates that the client is napping */
+	bool		listen;			/* whether an async query has been sent */
+	bool		is_throttled;	/* whether transaction throttling is done */
+	bool		sleeping;		/* whether the client is napping */
 	bool		throttling;		/* whether nap is for throttling */
 	Variable   *variables;		/* array of variable definitions */
 	int			nvariables;
 	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
-	bool		is_throttled;	/* whether transaction throttling is done */
 	int			use_file;		/* index in sql_scripts for this client */
 	bool		prepared[MAX_SCRIPTS]; /* whether client prepared the script */
 
@@ -1264,7 +1263,7 @@ top:
 			}
 		}
 
-		st->sleeping = 1;
+		st->sleeping = true;
 		st->throttling = true;
 		st->is_throttled = true;
 		if (debug)
@@ -1279,7 +1278,7 @@ top:
 		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
 		/* Else done sleeping, go ahead with next command */
-		st->sleeping = 0;
+		st->sleeping = false;
 		st->throttling = false;
 	}
 
@@ -1375,9 +1374,9 @@ top:
 			 * nothing to listen to right now.  When throttling rate limits
 			 * are active, a sleep will happen next, as the next transaction
 			 * starts.  And then in any case the next SQL command will set
-			 * listen back to 1.
+			 * listen back to true.
 			 */
-			st->listen = 0;
+			st->listen = false;
 			trans_needs_throttle = (throttle_delay > 0);
 		}
 	}
@@ -1500,7 +1499,7 @@ top:
 			st->ecnt++;
 		}
 		else
-			st->listen = 1;		/* flags that should be listened */
+			st->listen = true;		/* flags that should be listened */
 	}
 	else if (commands[st->state]->type == META_COMMAND)
 	{
@@ -1651,7 +1650,7 @@ top:
 				return true;
 			}
 
-			st->listen = 1;
+			st->listen = true;
 		}
 		else if (pg_strcasecmp(argv[0], "set") == 0)
 		{
@@ -1672,7 +1671,7 @@ top:
 				return true;
 			}
 
-			st->listen = 1;
+			st->listen = true;
 		}
 		else if (pg_strcasecmp(argv[0], "sleep") == 0)
 		{
@@ -1706,9 +1705,9 @@ top:
 
 			INSTR_TIME_SET_CURRENT(now);
 			st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now) + usec;
-			st->sleeping = 1;
+			st->sleeping = true;
 
-			st->listen = 1;
+			st->listen = true;
 		}
 		else if (pg_strcasecmp(argv[0], "setshell") == 0)
 		{
@@ -1722,7 +1721,7 @@ top:
 				return true;
 			}
 			else	/* succeeded */
-				st->listen = 1;
+				st->listen = true;
 		}
 		else if (pg_strcasecmp(argv[0], "shell") == 0)
 		{
@@ -1736,7 +1735,7 @@ top:
 				return true;
 			}
 			else	/* succeeded */
-				st->listen = 1;
+				st->listen = true;
 		}
 
 		/* after a meta command, immediately proceed with next command */
@@ -2822,12 +2821,14 @@ main(int argc, char **argv)
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
 		{"log", no_argument, NULL, 'l'},
+		{"latency-limit", required_argument, NULL, 'L'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
 		{"report-latencies", no_argument, NULL, 'r'},
+		{"rate", required_argument, NULL, 'R'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},
@@ -2842,8 +2843,6 @@ main(int argc, char **argv)
 		{"unlogged-tables", no_argument, &unlogged_tables, 1},
 		{"sampling-rate", required_argument, NULL, 4},
 		{"aggregate-interval", required_argument, NULL, 5},
-		{"rate", required_argument, NULL, 'R'},
-		{"latency-limit", required_argument, NULL, 'L'},
 		{"progress-timestamp", no_argument, NULL, 6},
 		{NULL, 0, NULL, 0}
 	};
@@ -3652,7 +3651,7 @@ threadRun(void *arg)
 				{
 					/* interrupt client which has not started a transaction */
 					remains--;
-					st->sleeping = 0;
+					st->sleeping = false;
 					st->throttling = false;
 					PQfinish(st->con);
 					st->con = NULL;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 541d17b..fdd3331 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -261,6 +261,23 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
     benchmarking arguments:
 
     <variablelist>
+     <varlistentry>
+      <term><option>-b</> <replaceable>scriptname</></term>
+      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <listitem>
+       <para>
+        Add the specified builtin script to the list of executed scripts.
+        Available builtin scripts are: <literal>tpcb-like</>,
+        <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only to be a prefix
+        of the builtin name, hence <literal>simp</> would be enough to select
+        <literal>simple-update</>.
+        With special name <literal>list</>, show the list of builtin scripts
+        and exit immediately.
+       </para>
+      </listitem>
+     </varlistentry>
+
 
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</></term>
@@ -307,14 +324,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</option> <replaceable>filename</></term>
-      <term><option>--file=</option><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename</></term>
+      <term><option>--file=</><replaceable>filename</></term>
       <listitem>
        <para>
-        Read transaction script from <replaceable>filename</>.
+        Add a transaction script read from <replaceable>filename</> to
+        the list of executed scripts.
         See below for details.
-        <option>-N</option>, <option>-S</option>, and <option>-f</option>
-        are mutually exclusive.
        </para>
       </listitem>
      </varlistentry>
@@ -404,10 +420,8 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--skip-some-updates</option></term>
       <listitem>
        <para>
-        Do not update <structname>pgbench_tellers</> and
-        <structname>pgbench_branches</>.
-        This will avoid update contention on these tables, but
-        it makes the test case even less like TPC-B.
+        Run builtin simple-update script.
+        Shorthand for <option>-b simple-update</>.
        </para>
       </listitem>
      </varlistentry>
@@ -512,9 +526,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Report the specified scale factor in <application>pgbench</>'s
         output.  With the built-in tests, this is not necessary; the
         correct scale factor will be detected by counting the number of
-        rows in the <structname>pgbench_branches</> table.  However, when testing
-        custom benchmarks (<option>-f</> option), the scale factor
-        will be reported as 1 unless this option is used.
+        rows in the <structname>pgbench_branches</> table.
+        However, when testing only custom benchmarks (<option>-f</> option),
+        the scale factor will be reported as 1 unless this option is used.
        </para>
       </listitem>
      </varlistentry>
@@ -524,7 +538,8 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
       <term><option>--select-only</option></term>
       <listitem>
        <para>
-        Perform select-only transactions instead of TPC-B-like test.
+        Run built-in select-only script.
+        Shorthand for <option>-b select-only</>.
        </para>
       </listitem>
      </varlistentry>
@@ -674,7 +689,17 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   The default transaction script issues seven commands per transaction:
+   Pgbench executes test scripts chosen randomly from a specified list.
+   They include built-in scripts with <option>-b</> and
+   user-provided custom scripts with <option>-f</>.
+ </para>
+
+  <para>
+   The default builtin transaction script (also invoked with <option>-b tpcb-like</>)
+   issues seven commands per transaction over randomly chosen <literal>aid</>,
+   <literal>tid</>, <literal>bid</> and <literal>balance</>.
+   The scenario is inspired by the TPC-B benchmark, but is not actually TPC-B,
+   hence the name.
   </para>
 
   <orderedlist>
@@ -688,9 +713,15 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   </orderedlist>
 
   <para>
-   If you specify <option>-N</>, steps 4 and 5 aren't included in the
-   transaction.  If you specify <option>-S</>, only the <command>SELECT</> is
-   issued.
+   If you select the <literal>simple-update</> builtin (also <option>-N</>),
+   steps 4 and 5 aren't included in the transaction.
+   This will avoid update contention on these tables, but
+   it makes the test case even less like TPC-B.
+  </para>
+
+  <para>
+   If you select the <literal>select-only</> builtin (also <option>-S</>),
+   only the <command>SELECT</> is issued.
   </para>
  </refsect2>
 
@@ -702,10 +733,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    benchmark scenarios by replacing the default transaction script
    (described above) with a transaction script read from a file
    (<option>-f</option> option).  In this case a <quote>transaction</>
-   counts as one execution of a script file.  You can even specify
-   multiple scripts (multiple <option>-f</option> options), in which
-   case a random one of the scripts is chosen each time a client session
-   starts a new transaction.
+   counts as one execution of a script file.
   </para>
 
   <para>
@@ -1112,7 +1140,8 @@ number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-statement latencies in milliseconds:
+SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
+ - per command latencies in ms:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
         0.001212        \set naccounts 100000 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 9e422c5..c8924d2 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -189,13 +189,12 @@ typedef struct
 	char	   *value;			/* its value */
 } Variable;
 
-#define MAX_FILES		128		/* max number of SQL script files allowed */
+#define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
- * structures used in custom query mode
+ * Connection state
  */
-
 typedef struct
 {
 	PGconn	   *con;			/* connection handle to DB */
@@ -211,8 +210,8 @@ typedef struct
 	instr_time	txn_begin;		/* used for measuring schedule lag times */
 	instr_time	stmt_begin;		/* used for measuring statement latencies */
 	bool		is_throttled;	/* whether transaction throttling is done */
-	int			use_file;		/* index in sql_files for this client */
-	bool		prepared[MAX_FILES];
+	int			use_file;		/* index in sql_scripts for this client */
+	bool		prepared[MAX_SCRIPTS];	/* whether client prepared the script */
 
 	/* per client collected stats */
 	int			cnt;			/* xacts count */
@@ -296,51 +295,68 @@ typedef struct
 	double		sum2_lag;		/* sum(lag*lag) */
 } AggVals;
 
-static Command **sql_files[MAX_FILES];	/* SQL script files */
-static int	num_files;			/* number of script files */
+static struct
+{
+	const char *name;
+	Command	 **commands;
+} sql_script[MAX_SCRIPTS];		/* SQL script files */
+static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
 static int	debug = 0;			/* debug flag */
 
-/* default scenario */
-static char *tpc_b = {
-	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
-	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"\\setrandom bid 1 :nbranches\n"
-	"\\setrandom tid 1 :ntellers\n"
-	"\\setrandom delta -5000 5000\n"
-	"BEGIN;\n"
-	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-	"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
-	"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
-	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-	"END;\n"
+/* Define builtin test scripts */
+#define N_BUILTIN 3
+static struct
+{
+	char	   *name;			/* very short name for -b ... */
+	char	   *desc;			/* short description */
+	char	   *commands;		/* actual pgbench script */
+}
+builtin_script[] =
+{
+	{
+		"tpcb-like",
+		"<builtin: TPC-B (sort of)>",
+		"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
+		"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
+		"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+		"\\setrandom aid 1 :naccounts\n"
+		"\\setrandom bid 1 :nbranches\n"
+		"\\setrandom tid 1 :ntellers\n"
+		"\\setrandom delta -5000 5000\n"
+		"BEGIN;\n"
+		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
+		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+		"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
+		"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
+		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
+		"END;\n"
+	},
+	{
+		"simple-update",
+		"<builtin: simple update>",
+		"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
+		"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
+		"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+		"\\setrandom aid 1 :naccounts\n"
+		"\\setrandom bid 1 :nbranches\n"
+		"\\setrandom tid 1 :ntellers\n"
+		"\\setrandom delta -5000 5000\n"
+		"BEGIN;\n"
+		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
+		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
+		"END;\n"
+	},
+	{
+		"select-only",
+		"<builtin: select only>",
+		"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
+		"\\setrandom aid 1 :naccounts\n"
+		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+	}
 };
 
-/* -N case */
-static char *simple_update = {
-	"\\set nbranches " CppAsString2(nbranches) " * :scale\n"
-	"\\set ntellers " CppAsString2(ntellers) " * :scale\n"
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"\\setrandom bid 1 :nbranches\n"
-	"\\setrandom tid 1 :ntellers\n"
-	"\\setrandom delta -5000 5000\n"
-	"BEGIN;\n"
-	"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-	"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-	"END;\n"
-};
-
-/* -S case */
-static char *select_only = {
-	"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
-	"\\setrandom aid 1 :naccounts\n"
-	"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
-};
 
 /* Function prototypes */
 static void setalarm(int seconds);
@@ -366,24 +382,29 @@ usage(void)
 	"                           create indexes in the specified tablespace\n"
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
+		   "\nOptions to select what to run:\n"
+		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
+		   "                           available scripts)\n"
+		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
+		   "                           (same as \"-b simple-update\")\n"
+		   "  -S, --select-only        perform SELECT-only transactions\n"
+		   "                           (same as \"-b select-only\")\n"
 		   "\nBenchmarking options:\n"
 		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
 		   "  -C, --connect            establish new connection for each transaction\n"
 		   "  -D, --define=VARNAME=VALUE\n"
 	  "                           define variable for use by custom script\n"
-		 "  -f, --file=FILENAME      read transaction script from FILENAME\n"
 		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
 		   "  -l, --log                write transaction times to log file\n"
 	"  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
 		   "  -M, --protocol=simple|extended|prepared\n"
 		   "                           protocol for submitting queries (default: simple)\n"
 		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
-		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
 		   "  -r, --report-latencies   report average latency per command\n"
 		"  -R, --rate=NUM           target rate in transactions per second\n"
 		   "  -s, --scale=NUM          report this scale factor in output\n"
-		   "  -S, --select-only        perform SELECT-only transactions\n"
 		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
 		 "  -T, --time=NUM           duration of benchmark test in seconds\n"
 		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
@@ -1124,6 +1145,15 @@ agg_vals_init(AggVals *aggs, instr_time start)
 	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
 }
 
+static int
+chooseScript(TState *thread)
+{
+	if (num_scripts == 1)
+		return 0;
+
+	return getrand(thread, 0, num_scripts - 1);
+}
+
 /* return false iff client should be disconnected */
 static bool
 doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
@@ -1144,7 +1174,7 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
 top:
 	INSTR_TIME_SET_ZERO(now);
 
-	commands = sql_files[st->use_file];
+	commands = sql_script[st->use_file].commands;
 
 	/*
 	 * Handle throttling once per transaction by sleeping.  It is simpler to
@@ -1328,8 +1358,11 @@ top:
 		if (commands[st->state] == NULL)
 		{
 			st->state = 0;
-			st->use_file = (int) getrand(thread, 0, num_files - 1);
-			commands = sql_files[st->use_file];
+			st->use_file = chooseScript(thread);
+			commands = sql_script[st->use_file].commands;
+			if (debug)
+				fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
+						sql_script[st->use_file].name);
 			st->is_throttled = false;
 
 			/*
@@ -2238,7 +2271,6 @@ static Command *
 process_commands(char *buf, const char *source, const int lineno)
 {
 	const char	delim[] = " \f\n\r\t\v";
-
 	Command    *my_commands;
 	int			j;
 	char	   *p,
@@ -2289,7 +2321,7 @@ process_commands(char *buf, const char *source, const int lineno)
 
 		if (pg_strcasecmp(my_commands->argv[0], "setrandom") == 0)
 		{
-			/*
+			/*--------
 			 * parsing:
 			 *   \setrandom variable min max [uniform]
 			 *   \setrandom variable min max (gaussian|exponential) parameter
@@ -2488,7 +2520,11 @@ read_line_from_file(FILE *fd)
 	return NULL;
 }
 
-static int
+/*
+ * Given a file name, read it and return the array of Commands contained
+ * therein.  "-" means to read stdin.
+ */
+static Command **
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
@@ -2500,12 +2536,6 @@ process_file(char *filename)
 	char	   *buf;
 	int			alloc_num;
 
-	if (num_files >= MAX_FILES)
-	{
-		fprintf(stderr, "at most %d SQL files are allowed\n", MAX_FILES);
-		exit(1);
-	}
-
 	alloc_num = COMMANDS_ALLOC_NUM;
 	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
@@ -2516,7 +2546,7 @@ process_file(char *filename)
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
 		pg_free(my_commands);
-		return false;
+		return NULL;
 	}
 
 	lineno = 0;
@@ -2548,13 +2578,11 @@ process_file(char *filename)
 
 	my_commands[index] = NULL;
 
-	sql_files[num_files++] = my_commands;
-
-	return true;
+	return my_commands;
 }
 
 static Command **
-process_builtin(char *tb, const char *source)
+process_builtin(const char *tb, const char *source)
 {
 #define COMMANDS_ALLOC_NUM 128
 
@@ -2608,9 +2636,60 @@ process_builtin(char *tb, const char *source)
 	return my_commands;
 }
 
+static void
+listAvailableScripts(void)
+{
+	int		i;
+
+	fprintf(stderr, "Available builtin scripts:\n");
+	for (i = 0; i < N_BUILTIN; i++)
+		fprintf(stderr, "\t%s\n", builtin_script[i].name);
+	fprintf(stderr, "\n");
+}
+
+static char *
+findBuiltin(const char *name, char **desc)
+{
+	int			len = strlen(name);
+	int			i;
+
+	for (i = 0; i < N_BUILTIN; i++)
+	{
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			*desc = builtin_script[i].desc;
+			return builtin_script[i].commands;
+		}
+	}
+
+	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	listAvailableScripts();
+	exit(1);
+}
+
+static void
+addScript(const char *name, Command **commands)
+{
+	if (commands == NULL)
+	{
+		fprintf(stderr, "empty command list for script \"%s\"\n", name);
+		exit(1);
+	}
+
+	if (num_scripts >= MAX_SCRIPTS)
+	{
+		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
+		exit(1);
+	}
+
+	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].commands = commands;
+	num_scripts++;
+}
+
 /* print out results */
 static void
-printResults(int ttype, int64 normal_xacts, int nclients,
+printResults(int64 normal_xacts, int nclients,
 			 TState *threads, int nthreads,
 			 instr_time total_time, instr_time conn_total_time,
 			 int64 total_latencies, int64 total_sqlats,
@@ -2620,23 +2699,14 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	double		time_include,
 				tps_include,
 				tps_exclude;
-	char	   *s;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
 	tps_include = normal_xacts / time_include;
 	tps_exclude = normal_xacts / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
-	if (ttype == 0)
-		s = "TPC-B (sort of)";
-	else if (ttype == 2)
-		s = "Update only pgbench_accounts";
-	else if (ttype == 1)
-		s = "SELECT only";
-	else
-		s = "Custom query";
-
-	printf("transaction type: %s\n", s);
+	printf("transaction type: %s\n",
+		   num_scripts == 1 ? sql_script[0].name : "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2705,16 +2775,14 @@ printResults(int ttype, int64 normal_xacts, int nclients,
 	{
 		int			i;
 
-		for (i = 0; i < num_files; i++)
+		for (i = 0; i < num_scripts; i++)
 		{
 			Command   **commands;
 
-			if (num_files > 1)
-				printf("statement latencies in milliseconds, file %d:\n", i + 1);
-			else
-				printf("statement latencies in milliseconds:\n");
+			printf("SQL script %d: %s\n", i + 1, sql_script[i].name);
+			printf(" - per command latencies in ms:\n");
 
-			for (commands = sql_files[i]; *commands != NULL; commands++)
+			for (commands = sql_script[i].commands; *commands != NULL; commands++)
 			{
 				Command    *command = *commands;
 				int			cnum = command->command_num;
@@ -2752,6 +2820,7 @@ main(int argc, char **argv)
 {
 	static struct option long_options[] = {
 		/* systematic long/short named options */
+		{"tpc-b", no_argument, NULL, 'b'},
 		{"client", required_argument, NULL, 'c'},
 		{"connect", no_argument, NULL, 'C'},
 		{"debug", no_argument, NULL, 'd'},
@@ -2794,14 +2863,12 @@ main(int argc, char **argv)
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
-	int			ttype = 0;		/* transaction type. 0: TPC-B, 1: SELECT only,
-								 * 2: skip update of branches and tellers */
 	int			optindex;
-	char	   *filename = NULL;
 	bool		scale_given = false;
 
 	bool		benchmarking_option_set = false;
 	bool		initialization_option_set = false;
+	bool		internal_script_used = false;
 
 	CState	   *state;			/* status of clients */
 	TState	   *threads;		/* array of thread */
@@ -2816,6 +2883,7 @@ main(int argc, char **argv)
 	int64		throttle_lag_max = 0;
 	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	char	   *desc;
 
 	int			i;
 	int			nclients_dealt;
@@ -2861,7 +2929,7 @@ main(int argc, char **argv)
 	state = (CState *) pg_malloc(sizeof(CState));
 	memset(state, 0, sizeof(CState));
 
-	while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
+	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
 		switch (c)
 		{
@@ -2883,14 +2951,6 @@ main(int argc, char **argv)
 			case 'd':
 				debug++;
 				break;
-			case 'S':
-				ttype = 1;
-				benchmarking_option_set = true;
-				break;
-			case 'N':
-				ttype = 2;
-				benchmarking_option_set = true;
-				break;
 			case 'c':
 				benchmarking_option_set = true;
 				nclients = atoi(optarg);
@@ -2993,12 +3053,36 @@ main(int argc, char **argv)
 				initialization_option_set = true;
 				use_quiet = true;
 				break;
-			case 'f':
+
+			case 'b':
+				if (strcmp(optarg, "list") == 0)
+				{
+					listAvailableScripts();
+					exit(0);
+				}
+
+				addScript(desc,
+						  process_builtin(findBuiltin(optarg, &desc), desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'S':
+				addScript(desc,
+						  process_builtin(findBuiltin("select-only", &desc),
+										 desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'N':
+				addScript(desc,
+						  process_builtin(findBuiltin("simple-update", &desc),
+										 desc));
+				benchmarking_option_set = true;
+				internal_script_used = true;
+				break;
+			case 'f':
+				addScript(optarg, process_file(optarg));
 				benchmarking_option_set = true;
-				ttype = 3;
-				filename = pg_strdup(optarg);
-				if (process_file(filename) == false || *sql_files[num_files - 1] == NULL)
-					exit(1);
 				break;
 			case 'D':
 				{
@@ -3029,9 +3113,9 @@ main(int argc, char **argv)
 				break;
 			case 'M':
 				benchmarking_option_set = true;
-				if (num_files > 0)
+				if (num_scripts > 0)
 				{
-					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f)\n");
+					fprintf(stderr, "query mode (-M) should be specified before any transaction scripts (-f or -b)\n");
 					exit(1);
 				}
 				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
@@ -3132,6 +3216,15 @@ main(int argc, char **argv)
 		}
 	}
 
+	/* set default script if none */
+	if (num_scripts == 0 && !is_init_mode)
+	{
+		addScript(desc,
+				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		benchmarking_option_set = true;
+		internal_script_used = true;
+	}
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some
@@ -3260,7 +3353,7 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	if (ttype != 3)
+	if (internal_script_used)
 	{
 		/*
 		 * get the scaling factor that should be same as count(*) from
@@ -3344,31 +3437,6 @@ main(int argc, char **argv)
 	INSTR_TIME_SET_CURRENT(start_time);
 	srandom((unsigned int) INSTR_TIME_GET_MICROSEC(start_time));
 
-	/* process builtin SQL scripts */
-	switch (ttype)
-	{
-		case 0:
-			sql_files[0] = process_builtin(tpc_b,
-										   "<builtin: TPC-B (sort of)>");
-			num_files = 1;
-			break;
-
-		case 1:
-			sql_files[0] = process_builtin(select_only,
-										   "<builtin: select only>");
-			num_files = 1;
-			break;
-
-		case 2:
-			sql_files[0] = process_builtin(simple_update,
-										   "<builtin: simple update>");
-			num_files = 1;
-			break;
-
-		default:
-			break;
-	}
-
 	/* set up thread data structures */
 	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
 	nclients_dealt = 0;
@@ -3499,7 +3567,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(ttype, total_xacts, nclients, threads, nthreads,
+	printResults(total_xacts, nclients, threads, nthreads,
 				 total_time, conn_total_time, total_latencies, total_sqlats,
 				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
 				 latency_late);
@@ -3583,10 +3651,14 @@ threadRun(void *arg)
 	for (i = 0; i < nstate; i++)
 	{
 		CState	   *st = &state[i];
-		Command   **commands = sql_files[st->use_file];
 		int			prev_ecnt = st->ecnt;
+		Command   **commands;
 
-		st->use_file = getrand(thread, 0, num_files - 1);
+		st->use_file = chooseScript(thread);
+		commands = sql_script[st->use_file].commands;
+		if (debug)
+			fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
+					sql_script[st->use_file].name);
 		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
 			remains--;			/* I've aborted */
 
@@ -3614,7 +3686,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			sock;
 
 			if (st->con == NULL)
@@ -3720,7 +3792,7 @@ threadRun(void *arg)
 		for (i = 0; i < nstate; i++)
 		{
 			CState	   *st = &state[i];
-			Command   **commands = sql_files[st->use_file];
+			Command   **commands = sql_script[st->use_file].commands;
 			int			prev_ecnt = st->ecnt;
 
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)

commit dd71004519237e9449bb1902de3004a01f695365
Author:     Alvaro Herrera <alvherre@alvh.no-ip.org>
AuthorDate: Tue Jan 26 10:12:51 2016 -0300
CommitDate: Wed Jan 27 02:57:18 2016 +0100

    apply 13-b, fix conflicts

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index d5f242c..305c319 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -166,10 +166,8 @@ int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;		/* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -193,6 +191,35 @@ typedef struct
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
+ * Simple data structure to keep stats about something.
+ *
+ * XXX probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64		count;			/* how many values were encountered */
+	double		min;			/* the minimum seen */
+	double		max;			/* the maximum seen */
+	double		sum;			/* sum of values */
+	double		sum2;			/* sum of squared values */
+} SimpleStats;
+
+/*
+ * Data structure to hold various statistics, used for interval statistics as
+ * well as file statistics.
+ */
+typedef struct
+{
+	long		start_time;		/* interval start time, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats latency;
+	SimpleStats lag;
+} StatsData;
+
+/*
  * Connection state
  */
 typedef struct
@@ -213,10 +240,8 @@ typedef struct
 	bool		prepared[MAX_SCRIPTS];	/* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -228,19 +253,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
 	unsigned short random_state[3];		/* separate randomness for each thread */
 	int64		throttle_trigger;		/* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData	stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -272,33 +292,14 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats stats;			/* time spent in this command */
 } Command;
 
-typedef struct
-{
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
 static struct
 {
 	const char *name;
-	Command	 **commands;
-} sql_script[MAX_SCRIPTS];		/* SQL script files */
+	Command   **commands;
+}	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
 static int	debug = 0;			/* debug flag */
@@ -361,9 +362,8 @@ static struct
 /* Function prototypes */
 static void setalarm(int seconds);
 static void *threadRun(void *arg);
+static void doTxStats(TState *, CState *, instr_time *, bool, FILE *, StatsData *);
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
 
 static void
 usage(void)
@@ -602,6 +602,63 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+/*
+ * Initialize the given SimpleStats struct to all zeroes
+ */
+static void
+initSimpleStats(SimpleStats *ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+/*
+ * Accumulate one value into a SimpleStats struct.
+ */
+static void
+addToSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+/*
+ * Merge two SimpleStats objects
+ */
+static void
+mergeSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+/*
+ * Initialize a StatsData struct to all zeroes.
+ *
+ * If the given start_time is different from 0.0, it is used; otherwise
+ * the original value is retained.
+ */
+static void
+initStats(StatsData *sd, double start_time)
+{
+	if (start_time != 0.0)
+		sd->start_time = start_time;
+
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(&sd->latency);
+	initSimpleStats(&sd->lag);
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1121,30 +1178,6 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
-{
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
-
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
-}
-
 static int
 chooseScript(TState *thread)
 {
@@ -1156,7 +1189,7 @@ chooseScript(TState *thread)
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1210,11 +1243,8 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st, &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
@@ -1231,28 +1261,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			/* Done sleeping, go ahead with next command */
-			st->sleeping = false;
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = 0;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1276,47 +1291,27 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/*
+			 * XXX When doing multiple threads, more than one could try to
+			 * update the stats for one command simultaneously.  Instead of
+			 * adding the overhead of a mutex, we accept the very small
+			 * probability of getting slightly wrong values.
+			 */
+			addToSimpleStats(&commands[st->state]->stats,
+							 INSTR_TIME_GET_DOUBLE(now) -
+							 INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1391,7 +1386,7 @@ top:
 			return clientDone(st, false);
 		}
 		INSTR_TIME_SET_CURRENT(end);
-		INSTR_TIME_ACCUM_DIFF(*conn_time, end, start);
+		INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	}
 
 	/*
@@ -1734,22 +1729,41 @@ top:
 			else	/* succeeded */
 				st->listen = true;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt++;
+
+	if (skipped)
+	{
+		/* no latency to record on skipped transactions */
+		stats->skipped++;
+	}
+	else
+	{
+		addToSimpleStats(&stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			addToSimpleStats(&stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1758,15 +1772,6 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
@@ -1776,39 +1781,7 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		 */
 		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
-			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
-			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
-
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			doStats(agg, skipped, latency, lag);
 		}
 		else
 		{
@@ -1823,52 +1796,34 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 				 * usage), so we don't need to handle this in a special way
 				 * (see below).
 				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
+				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
 						agg->start_time,
 						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
+						agg->latency.sum,
+						agg->latency.sum2,
+						agg->latency.min,
+						agg->latency.max);
 				if (throttle_delay)
 				{
 					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
+							agg->lag.sum,
+							agg->lag.sum2,
+							agg->lag.min,
+							agg->lag.max);
 					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
+						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 				}
 				fputc('\n', logfile);
 
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
+				/* move to the next interval */
+				agg->start_time += agg_interval;
 
 				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
+				initStats(agg, 0.0);
 			}
 
 			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
+			doStats(agg, skipped, latency, lag);
 		}
 	}
 	else
@@ -1878,21 +1833,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1901,6 +1856,42 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double		latency = 0.0,
+				lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(&thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2297,6 +2288,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(&my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2641,7 +2633,7 @@ process_builtin(const char *tb, const char *source)
 static void
 listAvailableScripts(void)
 {
-	int		i;
+	int			i;
 
 	fprintf(stderr, "Available builtin scripts:\n");
 	for (i = 0; i < N_BUILTIN; i++)
@@ -2689,22 +2681,29 @@ addScript(const char *name, Command **commands)
 	num_scripts++;
 }
 
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double		latency = ss->sum / ss->count;
+	double		stddev = sqrt(ss->sum2 / ss->count - latency * latency);
+
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
 	printf("transaction type: %s\n",
@@ -2716,46 +2715,36 @@ printResults(int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: " INT64_FORMAT "/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
 		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
 		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+			   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", &total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
 	{
@@ -2766,7 +2755,7 @@ printResults(int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 	}
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
@@ -2785,33 +2774,9 @@ printResults(int64 normal_xacts, int nclients,
 			printf(" - statement latencies in milliseconds:\n");
 
 			for (commands = sql_script[i].commands; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
-
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
-
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
-
-				printf("\t%f\t%s\n", total_time, command->line);
-			}
+				printf("   %11.3f  %s\n",
+				   1000.0 * (*commands)->stats.sum / (*commands)->stats.count,
+					   (*commands)->line);
 		}
 	}
 }
@@ -2860,8 +2825,6 @@ main(int argc, char **argv)
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
@@ -2878,13 +2841,8 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
 	char	   *desc;
 
 	int			i;
@@ -3071,14 +3029,14 @@ main(int argc, char **argv)
 			case 'S':
 				addScript(desc,
 						  process_builtin(findBuiltin("select-only", &desc),
-										 desc));
+										  desc));
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc,
 						  process_builtin(findBuiltin("simple-update", &desc),
-										 desc));
+										  desc));
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
@@ -3311,8 +3269,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3454,32 +3410,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(&thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3522,11 +3456,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(&stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3539,21 +3473,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		mergeSimpleStats(&stats.latency, &thread->stats.latency);
+		mergeSimpleStats(&stats.lag, &thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3569,10 +3495,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3593,13 +3516,8 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last,
+				aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3609,8 +3527,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3647,7 +3563,8 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
@@ -3661,7 +3578,7 @@ threadRun(void *arg)
 		if (debug)
 			fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
 					sql_script[st->use_file].name);
-		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+		if (!doCustom(thread, st, logfile, &aggs))
 			remains--;			/* I've aborted */
 
 		if (st->ecnt > prev_ecnt && commands[st->state]->type == META_COMMAND)
@@ -3800,7 +3717,7 @@ threadRun(void *arg)
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
 							|| commands[st->state]->type == META_COMMAND))
 			{
-				if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+				if (!doCustom(thread, st, logfile, &aggs))
 					remains--;	/* I've aborted */
 			}
 
@@ -3825,11 +3742,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData	cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3850,25 +3763,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(&cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
-				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					mergeSimpleStats(&cur.latency, &thread[i].stats.latency);
+					mergeSimpleStats(&cur.lag, &thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				if (progress_timestamp)
 					sprintf(tbuf, "%.03f s",
@@ -3885,16 +3797,12 @@ threadRun(void *arg)
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
 						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 42d0667..124e70d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -269,6 +269,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         Add the specified builtin script to the list of executed scripts.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only be an unambiguous
+        prefix of the builtin name, hence <literal>si</> would be enough to
+        select <literal>simple-update</>.
         With special name <literal>list</>, show the list of builtin scripts
         and exit immediately.
        </para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index d5f242c..6350948 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -2649,22 +2649,32 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
+/* return commands for selected builtin script, if unambiguous */
 static char *
 findBuiltin(const char *name, char **desc)
 {
-	int			i;
+	int			i, found = 0, len = strlen(name);
+	char	   *commands = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
-		if (strncmp(builtin_script[i].name, name,
-					strlen(builtin_script[i].name)) == 0)
+		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
 			*desc = builtin_script[i].desc;
-			return builtin_script[i].commands;
+			commands = builtin_script[i].commands;
+			found++;
 		}
 	}
 
-	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	if (found == 1)
+		return commands;
+
+	/* error cases */
+	if (found == 0)
+		fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	else /* found > 1 */
+		fprintf(stderr,
+				"%d builtin scripts found for prefix \"%s\"\n", found, name);
 	listAvailableScripts();
 	exit(1);
 }

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 42d0667..ade1b53 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1138,6 +1138,9 @@ number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
 SQL script 1: <builtin: TPC-B (sort of)>
+ - 10000 transactions (100.0% of total, tps = 618.764555)
+ - latency average = 15.844 ms
+ - latency stddev = 2.715 ms
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 305c319..5594d1c 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -164,6 +164,7 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
 int			nclients = 1;		/* number of clients */
@@ -299,6 +300,7 @@ static struct
 {
 	const char *name;
 	Command   **commands;
+	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
@@ -1308,7 +1310,7 @@ top:
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			if (progress || throttle_delay || latency_limit || logfile)
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
 				doTxStats(thread, st, &now, false, logfile, agg);
 			else
 				thread->stats.cnt++;
@@ -1401,7 +1403,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1889,6 +1891,9 @@ doTxStats(TState *thread, CState *st, instr_time *now,
 
 	if (use_log)
 		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		doStats(& sql_script[st->use_file].stats, skipped, latency, lag);
 }
 
 
@@ -2678,6 +2683,7 @@ addScript(const char *name, Command **commands)
 
 	sql_script[num_scripts].name = name;
 	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
 
@@ -2761,22 +2767,40 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-script stats */
+	if (per_script_stats)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i+1, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			printf("SQL script %d: %s\n", i + 1, sql_script[i].name);
-			printf(" - statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_script[i].commands; *commands != NULL; commands++)
-				printf("   %11.3f  %s\n",
-				   1000.0 * (*commands)->stats.sum / (*commands)->stats.count,
-					   (*commands)->line);
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
+
+				printf(" - per command latencies in ms:\n");
+
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
+			}
 		}
 	}
 }
@@ -2962,6 +2986,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -3185,6 +3210,10 @@ main(int argc, char **argv)
 		internal_script_used = true;
 	}
 
+	/* show per script stats if several scripts are used */
+	if (num_scripts > 1)
+		per_script_stats = true;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..ca3e158 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         With special name <literal>list</>, show the list of builtin scripts
@@ -321,12 +323,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -689,6 +693,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    Pgbench executes test scripts chosen randomly from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1137,7 +1144,7 @@ number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
+SQL script 1, weight 1: &lt;builtin: TPC-B (sort of)&gt;
  - 10000 transactions (100.0% of total, tps = 618.764555)
  - latency average = 15.844 ms
  - latency stddev = 2.715 ms
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 5594d1c..7aa6db7 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -179,6 +179,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -299,11 +301,14 @@ typedef struct
 static struct
 {
 	const char *name;
+	int weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
@@ -385,9 +390,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add weighted buitin script (use \"-b list\"\n"
+		   "                           to display available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add weighted transaction script from FILENAME\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1183,10 +1188,17 @@ clientDone(CState *st, bool ok)
 static int
 chooseScript(TState *thread)
 {
+	int i = 0, w = 0, wc;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	wc = (int) getrand(thread, 0, total_weight - 1);
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2666,8 +2678,41 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		char *s;
+		*sep++ = '\0';
+
+		/* check that the weight is a positive integer */
+		s = sep;
+		while ('0' <= *s && *s <= '9')
+			s++;
+		if (*s != '\0' || s == sep)
+		{
+			/* empty or any other char */
+			fprintf(stderr,
+					"weight for script \"%s\" must be an integer, got \"%s\"\n",
+					option, sep);
+			exit(1);
+		}
+
+		weight = atoi(sep);
+	}
+	else
+		weight = 1;
+
+	return weight;
+}
+
 static void
-addScript(const char *name, Command **commands)
+addScript(const char *name, Command **commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2682,6 +2727,7 @@ addScript(const char *name, Command **commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(& sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2767,16 +2813,16 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-script stats */
+	/* Report per-file data */
 	if (per_script_stats)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
+			printf("SQL script %d, weight %d: %s\n"
 				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
-				   i+1, sql_script[i].name,
+				   i+1, sql_script[i].weight, sql_script[i].name,
 				   sql_script[i].stats.cnt,
 				   100.0 * sql_script[i].stats.cnt / total->cnt,
 				   sql_script[i].stats.cnt / time_include);
@@ -2867,6 +2913,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
+	int			weight;
 	char	   *desc;
 
 	int			i;
@@ -3046,27 +3093,32 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
+				weight = getWeight(optarg);
 				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+						  process_builtin(findBuiltin(optarg, &desc), desc),
+						  weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'S':
 				addScript(desc,
 						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+										  desc),
+						  1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc,
 						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+										  desc),
+						  1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3205,11 +3257,16 @@ main(int argc, char **argv)
 	if (num_scripts == 0 && !is_init_mode)
 	{
 		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+				  process_builtin(findBuiltin("tpcb-like", &desc), desc),
+				  1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 7aa6db7..a4f9abf 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -1280,7 +1280,7 @@ top:
 		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
 		/* Else done sleeping, go ahead with next command */
-		st->sleeping = 0;
+		st->sleeping = false;
 		st->throttling = false;
 	}
 
@@ -2867,15 +2867,15 @@ main(int argc, char **argv)
 		{"host", required_argument, NULL, 'h'},
 		{"initialize", no_argument, NULL, 'i'},
 		{"jobs", required_argument, NULL, 'j'},
-		{"log", no_argument, NULL, 'l'},
 		{"latency-limit", required_argument, NULL, 'L'},
+		{"log", no_argument, NULL, 'l'},
 		{"no-vacuum", no_argument, NULL, 'n'},
 		{"port", required_argument, NULL, 'p'},
 		{"progress", required_argument, NULL, 'P'},
 		{"protocol", required_argument, NULL, 'M'},
 		{"quiet", no_argument, NULL, 'q'},
-		{"report-latencies", no_argument, NULL, 'r'},
 		{"rate", required_argument, NULL, 'R'},
+		{"report-latencies", no_argument, NULL, 'r'},
 		{"scale", required_argument, NULL, 's'},
 		{"select-only", no_argument, NULL, 'S'},
 		{"skip-some-updates", no_argument, NULL, 'N'},

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index d5f242c..b3fe994 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -166,10 +166,8 @@ int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
-int			progress_nclients = 0;		/* number of clients for progress
-										 * report */
-int			progress_nthreads = 0;		/* number of threads for progress
-										 * report */
+int			nclients = 1;		/* number of clients */
+int			nthreads = 1;		/* number of threads */
 bool		is_connect;			/* establish connection for each transaction */
 bool		is_latencies;		/* report per-command latencies */
 int			main_pid;			/* main process id used in log filename */
@@ -193,6 +191,35 @@ typedef struct
 #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
 
 /*
+ * Simple data structure to keep stats about something.
+ *
+ * XXX probably the first value should be kept and used as an offset for
+ * better numerical stability...
+ */
+typedef struct
+{
+	int64		count;			/* how many values were encountered */
+	double		min;			/* the minimum seen */
+	double		max;			/* the maximum seen */
+	double		sum;			/* sum of values */
+	double		sum2;			/* sum of squared values */
+} SimpleStats;
+
+/*
+ * Data structure to hold various statistics, used for interval statistics as
+ * well as file statistics.
+ */
+typedef struct
+{
+	long		start_time;		/* interval start time, for aggregates */
+	int64		cnt;			/* number of transactions */
+	int64		skipped;		/* number of transactions skipped under --rate
+								 * and --latency-limit */
+	SimpleStats latency;
+	SimpleStats lag;
+} StatsData;
+
+/*
  * Connection state
  */
 typedef struct
@@ -213,10 +240,8 @@ typedef struct
 	bool		prepared[MAX_SCRIPTS];	/* whether client prepared the script */
 
 	/* per client collected stats */
-	int			cnt;			/* xacts count */
+	int64		cnt;			/* transaction count */
 	int			ecnt;			/* error count */
-	int64		txn_latencies;	/* cumulated latencies */
-	int64		txn_sqlats;		/* cumulated square latencies */
 } CState;
 
 /*
@@ -228,19 +253,14 @@ typedef struct
 	pthread_t	thread;			/* thread handle */
 	CState	   *state;			/* array of CState */
 	int			nstate;			/* length of state[] */
-	instr_time	start_time;		/* thread start time */
-	instr_time *exec_elapsed;	/* time spent executing cmds (per Command) */
-	int		   *exec_count;		/* number of cmd executions (per Command) */
 	unsigned short random_state[3];		/* separate randomness for each thread */
 	int64		throttle_trigger;		/* previous/next throttling (us) */
 
 	/* per thread collected stats */
+	instr_time	start_time;		/* thread start time */
 	instr_time	conn_time;
-	int64		throttle_lag;	/* total transaction lag behind throttling */
-	int64		throttle_lag_max;		/* max transaction lag */
-	int64		throttle_latency_skipped;		/* lagging transactions
-												 * skipped */
-	int64		latency_late;	/* late transactions */
+	StatsData	stats;
+	int64		latency_late;	/* executed but late transactions */
 } TState;
 
 #define INVALID_THREAD		((pthread_t) 0)
@@ -272,33 +292,14 @@ typedef struct
 	char	   *argv[MAX_ARGS]; /* command word list */
 	int			cols[MAX_ARGS]; /* corresponding column starting from 1 */
 	PgBenchExpr *expr;			/* parsed expression */
+	SimpleStats stats;			/* time spent in this command */
 } Command;
 
-typedef struct
-{
-
-	long		start_time;		/* when does the interval start */
-	int			cnt;			/* number of transactions */
-	int			skipped;		/* number of transactions skipped under --rate
-								 * and --latency-limit */
-
-	double		min_latency;	/* min/max latencies */
-	double		max_latency;
-	double		sum_latency;	/* sum(latency), sum(latency^2) - for
-								 * estimates */
-	double		sum2_latency;
-
-	double		min_lag;
-	double		max_lag;
-	double		sum_lag;		/* sum(lag) */
-	double		sum2_lag;		/* sum(lag*lag) */
-} AggVals;
-
 static struct
 {
 	const char *name;
-	Command	 **commands;
-} sql_script[MAX_SCRIPTS];		/* SQL script files */
+	Command   **commands;
+}	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
 static int	debug = 0;			/* debug flag */
@@ -361,9 +362,8 @@ static struct
 /* Function prototypes */
 static void setalarm(int seconds);
 static void *threadRun(void *arg);
+static void doTxStats(TState *, CState *, instr_time *, bool, FILE *, StatsData *);
 
-static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
-	  AggVals *agg, bool skipped);
 
 static void
 usage(void)
@@ -602,6 +602,61 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+/*
+ * Initialize the given SimpleStats struct to all zeroes
+ */
+static void
+initSimpleStats(SimpleStats *ss)
+{
+	memset(ss, 0, sizeof(SimpleStats));
+}
+
+/*
+ * Accumulate one value into a SimpleStats struct.
+ */
+static void
+addToSimpleStats(SimpleStats *ss, double val)
+{
+	if (ss->count == 0 || val < ss->min)
+		ss->min = val;
+	if (ss->count == 0 || val > ss->max)
+		ss->max = val;
+	ss->count++;
+	ss->sum += val;
+	ss->sum2 += val * val;
+}
+
+/*
+ * Merge two SimpleStats objects
+ */
+static void
+mergeSimpleStats(SimpleStats *acc, SimpleStats *ss)
+{
+	if (acc->count == 0 || ss->min < acc->min)
+		acc->min = ss->min;
+	if (acc->count == 0 || ss->max > acc->max)
+		acc->max = ss->max;
+	acc->count += ss->count;
+	acc->sum += ss->sum;
+	acc->sum2 += ss->sum2;
+}
+
+/*
+ * Initialize a StatsData struct to all zeroes.
+ *
+ * If the given start_time is different from 0.0, it is used; otherwise
+ * the original value is retained.
+ */
+static void
+initStats(StatsData *sd, double start_time)
+{
+	sd->start_time = start_time;
+	sd->cnt = 0;
+	sd->skipped = 0;
+	initSimpleStats(&sd->latency);
+	initSimpleStats(&sd->lag);
+}
+
 /* call PQexec() and exit() on failure */
 static void
 executeStatement(PGconn *con, const char *sql)
@@ -1121,30 +1176,6 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
-static void
-agg_vals_init(AggVals *aggs, instr_time start)
-{
-	/* basic counters */
-	aggs->cnt = 0;				/* number of transactions (includes skipped) */
-	aggs->skipped = 0;			/* xacts skipped under --rate --latency-limit */
-
-	aggs->sum_latency = 0;		/* SUM(latency) */
-	aggs->sum2_latency = 0;		/* SUM(latency*latency) */
-
-	/* min and max transaction duration */
-	aggs->min_latency = 0;
-	aggs->max_latency = 0;
-
-	/* schedule lag counters */
-	aggs->sum_lag = 0;
-	aggs->sum2_lag = 0;
-	aggs->min_lag = 0;
-	aggs->max_lag = 0;
-
-	/* start of the current interval */
-	aggs->start_time = INSTR_TIME_GET_DOUBLE(start);
-}
-
 static int
 chooseScript(TState *thread)
 {
@@ -1156,7 +1187,7 @@ chooseScript(TState *thread)
 
 /* return false iff client should be disconnected */
 static bool
-doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVals *agg)
+doCustom(TState *thread, CState *st, FILE *logfile, StatsData *agg)
 {
 	PGresult   *res;
 	Command   **commands;
@@ -1210,11 +1241,8 @@ top:
 			now_us = INSTR_TIME_GET_MICROSEC(now);
 			while (thread->throttle_trigger < now_us - latency_limit)
 			{
-				thread->throttle_latency_skipped++;
-
-				if (logfile)
-					doLog(thread, st, logfile, &now, agg, true);
-
+				doTxStats(thread, st, &now, true, logfile, agg);
+				/* next rendez-vous */
 				wait = getPoissonRand(thread, throttle_delay);
 				thread->throttle_trigger += wait;
 				st->txn_scheduled = thread->throttle_trigger;
@@ -1231,28 +1259,13 @@ top:
 
 	if (st->sleeping)
 	{							/* are we sleeping? */
-		int64		now_us;
-
 		if (INSTR_TIME_IS_ZERO(now))
 			INSTR_TIME_SET_CURRENT(now);
-		now_us = INSTR_TIME_GET_MICROSEC(now);
-		if (st->txn_scheduled <= now_us)
-		{
-			/* Done sleeping, go ahead with next command */
-			st->sleeping = false;
-			if (st->throttling)
-			{
-				/* Measure lag of throttled transaction relative to target */
-				int64		lag = now_us - st->txn_scheduled;
-
-				thread->throttle_lag += lag;
-				if (lag > thread->throttle_lag_max)
-					thread->throttle_lag_max = lag;
-				st->throttling = false;
-			}
-		}
-		else
+		if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
 			return true;		/* Still sleeping, nothing to do here */
+		/* Else done sleeping, go ahead with next command */
+		st->sleeping = 0;
+		st->throttling = false;
 	}
 
 	if (st->listen)
@@ -1276,47 +1289,27 @@ top:
 		 */
 		if (is_latencies)
 		{
-			int			cnum = commands[st->state]->command_num;
-
 			if (INSTR_TIME_IS_ZERO(now))
 				INSTR_TIME_SET_CURRENT(now);
-			INSTR_TIME_ACCUM_DIFF(thread->exec_elapsed[cnum],
-								  now, st->stmt_begin);
-			thread->exec_count[cnum]++;
+
+			/*
+			 * XXX When doing multiple threads, more than one could try to
+			 * update the stats for one command simultaneously.  Instead of
+			 * adding the overhead of a mutex, we accept the very small
+			 * probability of getting slightly wrong values.
+			 */
+			addToSimpleStats(&commands[st->state]->stats,
+							 INSTR_TIME_GET_DOUBLE(now) -
+							 INSTR_TIME_GET_DOUBLE(st->stmt_begin));
 		}
 
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			/* only calculate latency if an option is used that needs it */
-			if (progress || throttle_delay || latency_limit)
-			{
-				int64		latency;
-
-				if (INSTR_TIME_IS_ZERO(now))
-					INSTR_TIME_SET_CURRENT(now);
-
-				latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
-
-				st->txn_latencies += latency;
-
-				/*
-				 * XXX In a long benchmark run of high-latency transactions,
-				 * this int64 addition eventually overflows.  For example, 100
-				 * threads running 10s transactions will overflow it in 2.56
-				 * hours.  With a more-typical OLTP workload of .1s
-				 * transactions, overflow would take 256 hours.
-				 */
-				st->txn_sqlats += latency * latency;
-
-				/* record over the limit transactions if needed. */
-				if (latency_limit && latency > latency_limit)
-					thread->latency_late++;
-			}
-
-			/* record the time it took in the log */
-			if (logfile)
-				doLog(thread, st, logfile, &now, agg, false);
+			if (progress || throttle_delay || latency_limit || logfile)
+				doTxStats(thread, st, &now, false, logfile, agg);
+			else
+				thread->stats.cnt++;
 		}
 
 		if (commands[st->state]->type == SQL_COMMAND)
@@ -1391,7 +1384,7 @@ top:
 			return clientDone(st, false);
 		}
 		INSTR_TIME_SET_CURRENT(end);
-		INSTR_TIME_ACCUM_DIFF(*conn_time, end, start);
+		INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	}
 
 	/*
@@ -1734,22 +1727,41 @@ top:
 			else	/* succeeded */
 				st->listen = true;
 		}
+
+		/* after a meta command, immediately proceed with next command */
 		goto top;
 	}
 
 	return true;
 }
 
+static void
+doStats(StatsData *stats, bool skipped, double lat, double lag)
+{
+	stats->cnt++;
+
+	if (skipped)
+	{
+		/* no latency to record on skipped transactions */
+		stats->skipped++;
+	}
+	else
+	{
+		addToSimpleStats(&stats->latency, lat);
+
+		/* and possibly the same for schedule lag */
+		if (throttle_delay)
+			addToSimpleStats(&stats->lag, lag);
+	}
+}
+
 /*
  * print log entry after completing one transaction.
  */
 static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
-	  bool skipped)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
+	  StatsData *agg, bool skipped, double latency, double lag)
 {
-	double		lag;
-	double		latency;
-
 	/*
 	 * Skip the log entry if sampling is enabled and this row doesn't belong
 	 * to the random sample.
@@ -1758,118 +1770,42 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 		pg_erand48(thread->random_state) > sample_rate)
 		return;
 
-	if (INSTR_TIME_IS_ZERO(*now))
-		INSTR_TIME_SET_CURRENT(*now);
-
-	latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
-	if (skipped)
-		lag = latency;
-	else
-		lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
-
 	/* should we aggregate the results or not? */
 	if (agg_interval > 0)
 	{
 		/*
-		 * Are we still in the same interval? If yes, accumulate the values
-		 * (print them otherwise)
+		 * Loop until we reach the interval of the current transaction,
+		 * and print all the empty intervals in between (this may happen
+		 * with very low tps, e.g. --rate=0.1).
 		 */
-		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
+		while (agg->start_time + agg_interval < INSTR_TIME_GET_DOUBLE(*now))
 		{
-			agg->cnt += 1;
-			if (skipped)
+			/* print aggregated report to logfile */
+			fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
+					agg->start_time,
+					agg->cnt,
+					agg->latency.sum,
+					agg->latency.sum2,
+					agg->latency.min,
+					agg->latency.max);
+			if (throttle_delay)
 			{
-				/*
-				 * there is no latency to record if the transaction was
-				 * skipped
-				 */
-				agg->skipped += 1;
+				fprintf(logfile, " %.0f %.0f %.0f %.0f",
+						agg->lag.sum,
+						agg->lag.sum2,
+						agg->lag.min,
+						agg->lag.max);
+				if (latency_limit)
+					fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 			}
-			else
-			{
-				agg->sum_latency += latency;
-				agg->sum2_latency += latency * latency;
-
-				/* first in this aggregation interval */
-				if ((agg->cnt == 1) || (latency < agg->min_latency))
-					agg->min_latency = latency;
-
-				if ((agg->cnt == 1) || (latency > agg->max_latency))
-					agg->max_latency = latency;
+			fputc('\n', logfile);
 
-				/* and the same for schedule lag */
-				if (throttle_delay)
-				{
-					agg->sum_lag += lag;
-					agg->sum2_lag += lag * lag;
-
-					if ((agg->cnt == 1) || (lag < agg->min_lag))
-						agg->min_lag = lag;
-					if ((agg->cnt == 1) || (lag > agg->max_lag))
-						agg->max_lag = lag;
-				}
-			}
+			/* reset data and move to next interval */
+			initStats(agg, agg->start_time + agg_interval);
 		}
-		else
-		{
-			/*
-			 * Loop until we reach the interval of the current transaction
-			 * (and print all the empty intervals in between).
-			 */
-			while (agg->start_time + agg_interval < INSTR_TIME_GET_DOUBLE(*now))
-			{
-				/*
-				 * This is a non-Windows branch (thanks to the ifdef in
-				 * usage), so we don't need to handle this in a special way
-				 * (see below).
-				 */
-				fprintf(logfile, "%ld %d %.0f %.0f %.0f %.0f",
-						agg->start_time,
-						agg->cnt,
-						agg->sum_latency,
-						agg->sum2_latency,
-						agg->min_latency,
-						agg->max_latency);
-				if (throttle_delay)
-				{
-					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->sum_lag,
-							agg->sum2_lag,
-							agg->min_lag,
-							agg->max_lag);
-					if (latency_limit)
-						fprintf(logfile, " %d", agg->skipped);
-				}
-				fputc('\n', logfile);
-
-				/* move to the next inteval */
-				agg->start_time = agg->start_time + agg_interval;
 
-				/* reset for "no transaction" intervals */
-				agg->cnt = 0;
-				agg->skipped = 0;
-				agg->min_latency = 0;
-				agg->max_latency = 0;
-				agg->sum_latency = 0;
-				agg->sum2_latency = 0;
-				agg->min_lag = 0;
-				agg->max_lag = 0;
-				agg->sum_lag = 0;
-				agg->sum2_lag = 0;
-			}
-
-			/* reset the values to include only the current transaction. */
-			agg->cnt = 1;
-			agg->skipped = skipped ? 1 : 0;
-			agg->min_latency = latency;
-			agg->max_latency = latency;
-			agg->sum_latency = skipped ? 0.0 : latency;
-			agg->sum2_latency = skipped ? 0.0 : latency * latency;
-			agg->min_lag = lag;
-			agg->max_lag = lag;
-			agg->sum_lag = lag;
-			agg->sum2_lag = lag * lag;
-		}
+		/* accumulate the current transaction */
+		doStats(agg, skipped, latency, lag);
 	}
 	else
 	{
@@ -1878,21 +1814,21 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 
 		/* This is more than we really ought to know about instr_time */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
 					st->id, st->cnt, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 		else
-			fprintf(logfile, "%d %d %.0f %d %ld %ld",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
 					st->id, st->cnt, latency, st->use_file,
 					(long) now->tv_sec, (long) now->tv_usec);
 #else
 
 		/* On Windows, instr_time doesn't provide a timestamp anyway */
 		if (skipped)
-			fprintf(logfile, "%d %d skipped %d 0 0",
+			fprintf(logfile, "%d " INT64_FORMAT " skipped %d 0 0",
 					st->id, st->cnt, st->use_file);
 		else
-			fprintf(logfile, "%d %d %.0f %d 0 0",
+			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d 0 0",
 					st->id, st->cnt, latency, st->use_file);
 #endif
 		if (throttle_delay)
@@ -1901,6 +1837,42 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
 	}
 }
 
+/*
+ * end of transaction statistics
+ */
+static void
+doTxStats(TState *thread, CState *st, instr_time *now,
+		  bool skipped, FILE *logfile, StatsData *agg)
+{
+	double		latency = 0.0,
+				lag = 0.0;
+
+	if ((!skipped || agg_interval) && INSTR_TIME_IS_ZERO(*now))
+		INSTR_TIME_SET_CURRENT(*now);
+
+	if (!skipped)
+	{
+		/* compute latency & lag if needed */
+		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
+		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
+	}
+
+	if (progress || throttle_delay || latency_limit)
+	{
+		doStats(&thread->stats, skipped, latency, lag);
+
+		/* record over the limit transactions if needed. */
+		if (latency_limit && latency > latency_limit)
+			thread->latency_late++;
+	}
+	else
+		thread->stats.cnt++;
+
+	if (use_log)
+		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+}
+
+
 /* discard connections */
 static void
 disconnect_all(CState *state, int length)
@@ -2297,6 +2269,7 @@ process_commands(char *buf, const char *source, const int lineno)
 	my_commands->command_num = num_commands++;
 	my_commands->type = 0;		/* until set */
 	my_commands->argc = 0;
+	initSimpleStats(&my_commands->stats);
 
 	if (*p == '\\')
 	{
@@ -2641,7 +2614,7 @@ process_builtin(const char *tb, const char *source)
 static void
 listAvailableScripts(void)
 {
-	int		i;
+	int			i;
 
 	fprintf(stderr, "Available builtin scripts:\n");
 	for (i = 0; i < N_BUILTIN; i++)
@@ -2689,22 +2662,29 @@ addScript(const char *name, Command **commands)
 	num_scripts++;
 }
 
+static void
+printSimpleStats(char *prefix, SimpleStats *ss)
+{
+	/* print NaN if no transactions where executed */
+	double		latency = ss->sum / ss->count;
+	double		stddev = sqrt(ss->sum2 / ss->count - latency * latency);
+
+	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+}
+
 /* print out results */
 static void
-printResults(int64 normal_xacts, int nclients,
-			 TState *threads, int nthreads,
-			 instr_time total_time, instr_time conn_total_time,
-			 int64 total_latencies, int64 total_sqlats,
-			 int64 throttle_lag, int64 throttle_lag_max,
-			 int64 throttle_latency_skipped, int64 latency_late)
+printResults(TState *threads, StatsData *total, instr_time total_time,
+			 instr_time conn_total_time, int latency_late)
 {
 	double		time_include,
 				tps_include,
 				tps_exclude;
 
 	time_include = INSTR_TIME_GET_DOUBLE(total_time);
-	tps_include = normal_xacts / time_include;
-	tps_exclude = normal_xacts / (time_include -
+	tps_include = total->cnt / time_include;
+	tps_exclude = total->cnt / (time_include -
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
 	printf("transaction type: %s\n",
@@ -2716,46 +2696,36 @@ printResults(int64 normal_xacts, int nclients,
 	if (duration <= 0)
 	{
 		printf("number of transactions per client: %d\n", nxacts);
-		printf("number of transactions actually processed: " INT64_FORMAT "/" INT64_FORMAT "\n",
-			   normal_xacts, (int64) nxacts * nclients);
+		printf("number of transactions actually processed: " INT64_FORMAT "/%d\n",
+			   total->cnt, nxacts * nclients);
 	}
 	else
 	{
 		printf("duration: %d s\n", duration);
 		printf("number of transactions actually processed: " INT64_FORMAT "\n",
-			   normal_xacts);
+			   total->cnt);
 	}
 
 	/* Remaining stats are nonsensical if we failed to execute any xacts */
-	if (normal_xacts <= 0)
+	if (total->cnt <= 0)
 		return;
 
 	if (throttle_delay && latency_limit)
 		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
-			   throttle_latency_skipped,
-			   100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+			   total->skipped,
+			   100.0 * total->skipped / (total->skipped + total->cnt));
 
 	if (latency_limit)
-		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+		printf("number of transactions above the %.1f ms latency limit: %d (%.3f %%)\n",
 			   latency_limit / 1000.0, latency_late,
-		   100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+			   100.0 * latency_late / (total->skipped + total->cnt));
 
 	if (throttle_delay || progress || latency_limit)
-	{
-		/* compute and show latency average and standard deviation */
-		double		latency = 0.001 * total_latencies / normal_xacts;
-		double		sqlat = (double) total_sqlats / normal_xacts;
-
-		printf("latency average: %.3f ms\n"
-			   "latency stddev: %.3f ms\n",
-			   latency, 0.001 * sqrt(sqlat - 1000000.0 * latency * latency));
-	}
+		printSimpleStats("latency", &total->latency);
 	else
-	{
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / normal_xacts);
-	}
+			   1000.0 * duration * nclients / total->cnt);
 
 	if (throttle_delay)
 	{
@@ -2766,7 +2736,7 @@ printResults(int64 normal_xacts, int nclients,
 		 * the database load, or the Poisson throttling process.
 		 */
 		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
-			   0.001 * throttle_lag / normal_xacts, 0.001 * throttle_lag_max);
+			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
 	}
 
 	printf("tps = %f (including connections establishing)\n", tps_include);
@@ -2785,33 +2755,9 @@ printResults(int64 normal_xacts, int nclients,
 			printf(" - statement latencies in milliseconds:\n");
 
 			for (commands = sql_script[i].commands; *commands != NULL; commands++)
-			{
-				Command    *command = *commands;
-				int			cnum = command->command_num;
-				double		total_time;
-				instr_time	total_exec_elapsed;
-				int			total_exec_count;
-				int			t;
-
-				/* Accumulate per-thread data for command */
-				INSTR_TIME_SET_ZERO(total_exec_elapsed);
-				total_exec_count = 0;
-				for (t = 0; t < nthreads; t++)
-				{
-					TState	   *thread = &threads[t];
-
-					INSTR_TIME_ADD(total_exec_elapsed,
-								   thread->exec_elapsed[cnum]);
-					total_exec_count += thread->exec_count[cnum];
-				}
-
-				if (total_exec_count > 0)
-					total_time = INSTR_TIME_GET_MILLISEC(total_exec_elapsed) / (double) total_exec_count;
-				else
-					total_time = 0.0;
-
-				printf("\t%f\t%s\n", total_time, command->line);
-			}
+				printf("   %11.3f  %s\n",
+				   1000.0 * (*commands)->stats.sum / (*commands)->stats.count,
+					   (*commands)->line);
 		}
 	}
 }
@@ -2860,8 +2806,6 @@ main(int argc, char **argv)
 	};
 
 	int			c;
-	int			nclients = 1;	/* default number of simulated clients */
-	int			nthreads = 1;	/* default number of threads */
 	int			is_init_mode = 0;		/* initialize mode? */
 	int			is_no_vacuum = 0;		/* no vacuum at all before testing? */
 	int			do_vacuum_accounts = 0; /* do vacuum accounts before testing? */
@@ -2878,13 +2822,8 @@ main(int argc, char **argv)
 	instr_time	start_time;		/* start up time */
 	instr_time	total_time;
 	instr_time	conn_total_time;
-	int64		total_xacts = 0;
-	int64		total_latencies = 0;
-	int64		total_sqlats = 0;
-	int64		throttle_lag = 0;
-	int64		throttle_lag_max = 0;
-	int64		throttle_latency_skipped = 0;
 	int64		latency_late = 0;
+	StatsData	stats;
 	char	   *desc;
 
 	int			i;
@@ -3071,14 +3010,14 @@ main(int argc, char **argv)
 			case 'S':
 				addScript(desc,
 						  process_builtin(findBuiltin("select-only", &desc),
-										 desc));
+										  desc));
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc,
 						  process_builtin(findBuiltin("simple-update", &desc),
-										 desc));
+										  desc));
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
@@ -3311,8 +3250,6 @@ main(int argc, char **argv)
 	 * changed after fork.
 	 */
 	main_pid = (int) getpid();
-	progress_nclients = nclients;
-	progress_nthreads = nthreads;
 
 	if (nclients > 1)
 	{
@@ -3454,32 +3391,10 @@ main(int argc, char **argv)
 		thread->random_state[0] = random();
 		thread->random_state[1] = random();
 		thread->random_state[2] = random();
-		thread->throttle_latency_skipped = 0;
 		thread->latency_late = 0;
+		initStats(&thread->stats, 0.0);
 
 		nclients_dealt += thread->nstate;
-
-		if (is_latencies)
-		{
-			/* Reserve memory for the thread to store per-command latencies */
-			int			t;
-
-			thread->exec_elapsed = (instr_time *)
-				pg_malloc(sizeof(instr_time) * num_commands);
-			thread->exec_count = (int *)
-				pg_malloc(sizeof(int) * num_commands);
-
-			for (t = 0; t < num_commands; t++)
-			{
-				INSTR_TIME_SET_ZERO(thread->exec_elapsed[t]);
-				thread->exec_count[t] = 0;
-			}
-		}
-		else
-		{
-			thread->exec_elapsed = NULL;
-			thread->exec_count = NULL;
-		}
 	}
 
 	/* all clients must be assigned to a thread */
@@ -3522,11 +3437,11 @@ main(int argc, char **argv)
 #endif   /* ENABLE_THREAD_SAFETY */
 
 	/* wait for threads and accumulate results */
+	initStats(&stats, 0.0);
 	INSTR_TIME_SET_ZERO(conn_total_time);
 	for (i = 0; i < nthreads; i++)
 	{
 		TState	   *thread = &threads[i];
-		int			j;
 
 #ifdef ENABLE_THREAD_SAFETY
 		if (threads[i].thread == INVALID_THREAD)
@@ -3539,21 +3454,13 @@ main(int argc, char **argv)
 		(void) threadRun(thread);
 #endif   /* ENABLE_THREAD_SAFETY */
 
-		/* thread level stats */
-		throttle_lag += thread->throttle_lag;
-		throttle_latency_skipped += threads->throttle_latency_skipped;
+		/* aggregate thread level stats */
+		mergeSimpleStats(&stats.latency, &thread->stats.latency);
+		mergeSimpleStats(&stats.lag, &thread->stats.lag);
+		stats.cnt += thread->stats.cnt;
+		stats.skipped += thread->stats.skipped;
 		latency_late += thread->latency_late;
-		if (throttle_lag_max > thread->throttle_lag_max)
-			throttle_lag_max = thread->throttle_lag_max;
 		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
-
-		/* client-level stats */
-		for (j = 0; j < thread->nstate; j++)
-		{
-			total_xacts += thread->state[j].cnt;
-			total_latencies += thread->state[j].txn_latencies;
-			total_sqlats += thread->state[j].txn_sqlats;
-		}
 	}
 	disconnect_all(state, nclients);
 
@@ -3569,10 +3476,7 @@ main(int argc, char **argv)
 	 */
 	INSTR_TIME_SET_CURRENT(total_time);
 	INSTR_TIME_SUBTRACT(total_time, start_time);
-	printResults(total_xacts, nclients, threads, nthreads,
-				 total_time, conn_total_time, total_latencies, total_sqlats,
-				 throttle_lag, throttle_lag_max, throttle_latency_skipped,
-				 latency_late);
+	printResults(threads, &stats, total_time, conn_total_time, latency_late);
 
 	return 0;
 }
@@ -3593,13 +3497,8 @@ threadRun(void *arg)
 	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
 	int64		last_report = thread_start;
 	int64		next_report = last_report + (int64) progress * 1000000;
-	int64		last_count = 0,
-				last_lats = 0,
-				last_sqlats = 0,
-				last_lags = 0,
-				last_skipped = 0;
-
-	AggVals		aggs;
+	StatsData	last,
+				aggs;
 
 	/*
 	 * Initialize throttling rate target for all of the thread's clients.  It
@@ -3609,8 +3508,6 @@ threadRun(void *arg)
 	 */
 	INSTR_TIME_SET_CURRENT(start);
 	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
-	thread->throttle_lag = 0;
-	thread->throttle_lag_max = 0;
 
 	INSTR_TIME_SET_ZERO(thread->conn_time);
 
@@ -3647,7 +3544,8 @@ threadRun(void *arg)
 	INSTR_TIME_SET_CURRENT(thread->conn_time);
 	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
 
-	agg_vals_init(&aggs, thread->start_time);
+	initStats(&aggs, INSTR_TIME_GET_DOUBLE(thread->start_time));
+	last = aggs;
 
 	/* send start up queries in async manner */
 	for (i = 0; i < nstate; i++)
@@ -3661,7 +3559,7 @@ threadRun(void *arg)
 		if (debug)
 			fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
 					sql_script[st->use_file].name);
-		if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+		if (!doCustom(thread, st, logfile, &aggs))
 			remains--;			/* I've aborted */
 
 		if (st->ecnt > prev_ecnt && commands[st->state]->type == META_COMMAND)
@@ -3800,7 +3698,7 @@ threadRun(void *arg)
 			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
 							|| commands[st->state]->type == META_COMMAND))
 			{
-				if (!doCustom(thread, st, &thread->conn_time, logfile, &aggs))
+				if (!doCustom(thread, st, logfile, &aggs))
 					remains--;	/* I've aborted */
 			}
 
@@ -3825,11 +3723,7 @@ threadRun(void *arg)
 			if (now >= next_report)
 			{
 				/* generate and show report */
-				int64		count = 0,
-							lats = 0,
-							sqlats = 0,
-							lags = 0,
-							skipped = 0;
+				StatsData	cur;
 				int64		run = now - last_report;
 				double		tps,
 							total_run,
@@ -3850,25 +3744,24 @@ threadRun(void *arg)
 				 * (If a read from a 64-bit integer is not atomic, you might
 				 * get a "torn" read and completely bogus latencies though!)
 				 */
-				for (i = 0; i < progress_nclients; i++)
+				initStats(&cur, 0.0);
+				for (i = 0; i < nthreads; i++)
 				{
-					count += state[i].cnt;
-					lats += state[i].txn_latencies;
-					sqlats += state[i].txn_sqlats;
-				}
-
-				for (i = 0; i < progress_nthreads; i++)
-				{
-					skipped += thread[i].throttle_latency_skipped;
-					lags += thread[i].throttle_lag;
+					mergeSimpleStats(&cur.latency, &thread[i].stats.latency);
+					mergeSimpleStats(&cur.lag, &thread[i].stats.lag);
+					cur.cnt += thread[i].stats.cnt;
+					cur.skipped += thread[i].stats.skipped;
 				}
 
 				total_run = (now - thread_start) / 1000000.0;
-				tps = 1000000.0 * (count - last_count) / run;
-				latency = 0.001 * (lats - last_lats) / (count - last_count);
-				sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
+				tps = 1000000.0 * (cur.cnt - last.cnt) / run;
+				latency = 0.001 * (cur.latency.sum - last.latency.sum) /
+					(cur.cnt - last.cnt);
+				sqlat = 1.0 * (cur.latency.sum2 - last.latency.sum2)
+					/ (cur.cnt - last.cnt);
 				stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
-				lag = 0.001 * (lags - last_lags) / (count - last_count);
+				lag = 0.001 * (cur.lag.sum - last.lag.sum) /
+					(cur.cnt - last.cnt);
 
 				if (progress_timestamp)
 					sprintf(tbuf, "%.03f s",
@@ -3885,16 +3778,12 @@ threadRun(void *arg)
 					fprintf(stderr, ", lag %.3f ms", lag);
 					if (latency_limit)
 						fprintf(stderr, ", " INT64_FORMAT " skipped",
-								skipped - last_skipped);
+								cur.skipped - last.skipped);
 				}
 				fprintf(stderr, "\n");
 
-				last_count = count;
-				last_lats = lats;
-				last_sqlats = sqlats;
-				last_lags = lags;
+				last = cur;
 				last_report = now;
-				last_skipped = skipped;
 
 				/*
 				 * Ensure that the next report is in the future, in case
@@ -3914,7 +3803,12 @@ done:
 	INSTR_TIME_SET_CURRENT(end);
 	INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	if (logfile)
+	{
+		if (agg_interval)
+			/* log aggregated but not yet reported transactions */
+			doLog(thread, state, logfile, &end, &aggs, false, 0, 0);
 		fclose(logfile);
+	}
 	return NULL;
 }
 

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 305c319..b3fe994 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -650,9 +650,7 @@ mergeSimpleStats(SimpleStats *acc, SimpleStats *ss)
 static void
 initStats(StatsData *sd, double start_time)
 {
-	if (start_time != 0.0)
-		sd->start_time = start_time;
-
+	sd->start_time = start_time;
 	sd->cnt = 0;
 	sd->skipped = 0;
 	initSimpleStats(&sd->latency);
@@ -1776,55 +1774,38 @@ doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
 	if (agg_interval > 0)
 	{
 		/*
-		 * Are we still in the same interval? If yes, accumulate the values
-		 * (print them otherwise)
+		 * Loop until we reach the interval of the current transaction,
+		 * and print all the empty intervals in between (this may happen
+		 * with very low tps, e.g. --rate=0.1).
 		 */
-		if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
+		while (agg->start_time + agg_interval < INSTR_TIME_GET_DOUBLE(*now))
 		{
-			doStats(agg, skipped, latency, lag);
-		}
-		else
-		{
-			/*
-			 * Loop until we reach the interval of the current transaction
-			 * (and print all the empty intervals in between).
-			 */
-			while (agg->start_time + agg_interval < INSTR_TIME_GET_DOUBLE(*now))
+			/* print aggregated report to logfile */
+			fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
+					agg->start_time,
+					agg->cnt,
+					agg->latency.sum,
+					agg->latency.sum2,
+					agg->latency.min,
+					agg->latency.max);
+			if (throttle_delay)
 			{
-				/*
-				 * This is a non-Windows branch (thanks to the ifdef in
-				 * usage), so we don't need to handle this in a special way
-				 * (see below).
-				 */
-				fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
-						agg->start_time,
-						agg->cnt,
-						agg->latency.sum,
-						agg->latency.sum2,
-						agg->latency.min,
-						agg->latency.max);
-				if (throttle_delay)
-				{
-					fprintf(logfile, " %.0f %.0f %.0f %.0f",
-							agg->lag.sum,
-							agg->lag.sum2,
-							agg->lag.min,
-							agg->lag.max);
-					if (latency_limit)
-						fprintf(logfile, " " INT64_FORMAT, agg->skipped);
-				}
-				fputc('\n', logfile);
-
-				/* move to the next interval */
-				agg->start_time += agg_interval;
-
-				/* reset for "no transaction" intervals */
-				initStats(agg, 0.0);
+				fprintf(logfile, " %.0f %.0f %.0f %.0f",
+						agg->lag.sum,
+						agg->lag.sum2,
+						agg->lag.min,
+						agg->lag.max);
+				if (latency_limit)
+					fprintf(logfile, " " INT64_FORMAT, agg->skipped);
 			}
+			fputc('\n', logfile);
 
-			/* reset the values to include only the current transaction. */
-			doStats(agg, skipped, latency, lag);
+			/* reset data and move to next interval */
+			initStats(agg, agg->start_time + agg_interval);
 		}
+
+		/* accumulate the current transaction */
+		doStats(agg, skipped, latency, lag);
 	}
 	else
 	{
@@ -3822,7 +3803,12 @@ done:
 	INSTR_TIME_SET_CURRENT(end);
 	INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
 	if (logfile)
+	{
+		if (agg_interval)
+			/* log aggregated but not yet reported transactions */
+			doLog(thread, state, logfile, &end, &aggs, false, 0, 0);
 		fclose(logfile);
+	}
 	return NULL;
 }
 

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 42d0667..ade1b53 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1138,6 +1138,9 @@ number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
 SQL script 1: <builtin: TPC-B (sort of)>
+ - 10000 transactions (100.0% of total, tps = 618.764555)
+ - latency average = 15.844 ms
+ - latency stddev = 2.715 ms
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 44da3d1..64c7a6c 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -164,6 +164,7 @@ bool		use_log;			/* log transaction latencies to a file */
 bool		use_quiet;			/* quiet logging onto stderr */
 int			agg_interval;		/* log aggregates instead of individual
 								 * transactions */
+bool        per_script_stats = false; /* whether to collect stats per script */
 int			progress = 0;		/* thread progress report every this seconds */
 bool		progress_timestamp = false; /* progress report with Unix time */
 int			nclients = 1;		/* number of clients */
@@ -299,6 +300,7 @@ static struct
 {
 	const char *name;
 	Command   **commands;
+	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
@@ -1326,7 +1328,7 @@ top:
 		/* transaction finished: calculate latency and log the transaction */
 		if (commands[st->state + 1] == NULL)
 		{
-			if (progress || throttle_delay || latency_limit || logfile)
+			if (progress || throttle_delay || latency_limit || per_script_stats || logfile)
 				processXactStats(thread, st, &now, false, logfile, agg);
 			else
 				thread->stats.cnt++;
@@ -1419,7 +1421,7 @@ top:
 	}
 
 	/* Record transaction start time under logging, progress or throttling */
-	if ((logfile || progress || throttle_delay || latency_limit) && st->state == 0)
+	if ((logfile || progress || throttle_delay || latency_limit || per_script_stats) && st->state == 0)
 	{
 		INSTR_TIME_SET_CURRENT(st->txn_begin);
 
@@ -1872,6 +1874,9 @@ processXactStats(TState *thread, CState *st, instr_time *now,
 
 	if (use_log)
 		doLog(thread, st, logfile, now, agg, skipped, latency, lag);
+
+	if (per_script_stats) /* mutex? hmmm... these are only statistics */
+		accumStats(& sql_script[st->use_file].stats, skipped, latency, lag);
 }
 
 
@@ -2661,6 +2666,7 @@ addScript(const char *name, Command **commands)
 
 	sql_script[num_scripts].name = name;
 	sql_script[num_scripts].commands = commands;
+	initStats(& sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
 
@@ -2744,22 +2750,40 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command latencies */
-	if (is_latencies)
+	/* Report per-script stats */
+	if (per_script_stats)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			Command   **commands;
+			printf("SQL script %d: %s\n"
+				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i + 1, sql_script[i].name,
+				   sql_script[i].stats.cnt,
+				   100.0 * sql_script[i].stats.cnt / total->cnt,
+				   sql_script[i].stats.cnt / time_include);
 
-			printf("SQL script %d: %s\n", i + 1, sql_script[i].name);
-			printf(" - statement latencies in milliseconds:\n");
+			if (latency_limit)
+				printf(" - number of transactions skipped: "INT64_FORMAT" (%.3f%%)\n",
+					   sql_script[i].stats.skipped,
+					   100.0 * sql_script[i].stats.skipped /
+					   (sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			for (commands = sql_script[i].commands; *commands != NULL; commands++)
-				printf("   %11.3f  %s\n",
-				  1000.0 * (*commands)->stats.sum / (*commands)->stats.count,
-					   (*commands)->line);
+			printSimpleStats(" - latency", & sql_script[i].stats.latency);
+
+			/* Report per-command latencies */
+			if (is_latencies)
+			{
+				Command ** com;
+
+				printf(" - statement latencies in milliseconds:\n");
+
+				for (com = sql_script[i].commands; *com != NULL; com++)
+					printf("   %11.3f  %s\n",
+						   1000.0 * (*com)->stats.sum / (*com)->stats.count,
+						   (*com)->line);
+			}
 		}
 	}
 }
@@ -2945,6 +2969,7 @@ main(int argc, char **argv)
 				break;
 			case 'r':
 				benchmarking_option_set = true;
+				per_script_stats = true;
 				is_latencies = true;
 				break;
 			case 's':
@@ -3168,6 +3193,10 @@ main(int argc, char **argv)
 		internal_script_used = true;
 	}
 
+	/* show per script stats if several scripts are used */
+	if (num_scripts > 1)
+		per_script_stats = true;
+
 	/*
 	 * Don't need more threads than there are clients.  (This is not merely an
 	 * optimization; throttle_delay is calculated incorrectly below if some

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..ca3e158 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         With special name <literal>list</>, show the list of builtin scripts
@@ -321,12 +323,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -689,6 +693,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    Pgbench executes test scripts chosen randomly from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1137,7 +1144,7 @@ number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
+SQL script 1, weight 1: &lt;builtin: TPC-B (sort of)&gt;
  - 10000 transactions (100.0% of total, tps = 618.764555)
  - latency average = 15.844 ms
  - latency stddev = 2.715 ms
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 64c7a6c..f77c7c6 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -179,6 +179,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -299,11 +301,14 @@ typedef struct
 static struct
 {
 	const char *name;
+	int weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
@@ -389,9 +394,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add weighted buitin script (use \"-b list\"\n"
+		   "                           to display available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add weighted transaction script from FILENAME\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1206,10 +1211,17 @@ clientDone(CState *st, bool ok)
 static int
 chooseScript(TState *thread)
 {
+	int i = 0, w = 0, wc;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	wc = (int) getrand(thread, 0, total_weight - 1);
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2649,8 +2661,41 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		char *s;
+		*sep++ = '\0';
+
+		/* check that the weight is a positive integer */
+		s = sep;
+		while ('0' <= *s && *s <= '9')
+			s++;
+		if (*s != '\0' || s == sep)
+		{
+			/* empty or any other char */
+			fprintf(stderr,
+					"weight for script \"%s\" must be an integer, got \"%s\"\n",
+					option, sep);
+			exit(1);
+		}
+
+		weight = atoi(sep);
+	}
+	else
+		weight = 1;
+
+	return weight;
+}
+
 static void
-addScript(const char *name, Command **commands)
+addScript(const char *name, Command **commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2665,6 +2710,7 @@ addScript(const char *name, Command **commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(& sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2757,9 +2803,9 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
+			printf("SQL script %d, weight %d: %s\n"
 				   " - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
+				   i + 1, sql_script[i].weight, sql_script[i].name,
 				   sql_script[i].stats.cnt,
 				   100.0 * sql_script[i].stats.cnt / total->cnt,
 				   sql_script[i].stats.cnt / time_include);
@@ -2850,6 +2896,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
+	int			weight;
 	char	   *desc;
 
 	int			i;
@@ -3029,27 +3076,32 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
+				weight = getWeight(optarg);
 				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+						  process_builtin(findBuiltin(optarg, &desc), desc),
+						  weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'S':
 				addScript(desc,
 						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+										  desc),
+						  1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc,
 						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+										  desc),
+						  1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3188,11 +3240,16 @@ main(int argc, char **argv)
 	if (num_scripts == 0 && !is_init_mode)
 	{
 		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+				  process_builtin(findBuiltin("tpcb-like", &desc), desc),
+				  1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ca3e158..52dc142 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -271,6 +271,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         probability of drawing the test.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only be an unambiguous
+        prefix of the builtin name, hence <literal>si</> would be enough to
+        select <literal>simple-update</>.
         With special name <literal>list</>, show the list of builtin scripts
         and exit immediately.
        </para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index f77c7c6..5b4424e 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -2641,22 +2641,32 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
+/* return commands for selected builtin script, if unambiguous */
 static char *
 findBuiltin(const char *name, char **desc)
 {
-	int			i;
+	int			i, found = 0, len = strlen(name);
+	char	   *commands = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
-		if (strncmp(builtin_script[i].name, name,
-					strlen(builtin_script[i].name)) == 0)
+		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
 			*desc = builtin_script[i].desc;
-			return builtin_script[i].commands;
+			commands = builtin_script[i].commands;
+			found++;
 		}
 	}
 
-	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	if (found == 1)
+		return commands;
+
+	/* error cases */
+	if (found == 0)
+		fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	else /* found > 1 */
+		fprintf(stderr,
+				"%d builtin scripts found for prefix \"%s\"\n", found, name);
 	listAvailableScripts();
 	exit(1);
 }

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ca3e158..52dc142 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -271,6 +271,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         probability of drawing the test.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only be an unambiguous
+        prefix of the builtin name, hence <literal>si</> would be enough to
+        select <literal>simple-update</>.
         With special name <literal>list</>, show the list of builtin scripts
         and exit immediately.
        </para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 5d24768..783cbf9 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -2675,22 +2675,32 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
+/* return commands for selected builtin script, if unambiguous */
 static char *
 findBuiltin(const char *name, char **desc)
 {
-	int			i;
+	int			i, found = 0, len = strlen(name);
+	char	   *commands = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
-		if (strncmp(builtin_script[i].name, name,
-					strlen(builtin_script[i].name)) == 0)
+		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
 			*desc = builtin_script[i].desc;
-			return builtin_script[i].commands;
+			commands = builtin_script[i].commands;
+			found++;
 		}
 	}
 
-	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	if (found == 1)
+		return commands;
+
+	/* error cases */
+	if (found == 0)
+		fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	else /* found > 1 */
+		fprintf(stderr,
+				"%d builtin scripts found for prefix \"%s\"\n", found, name);
 	listAvailableScripts();
 	exit(1);
 }

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..ca3e158 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</> <replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         With special name <literal>list</>, show the list of builtin scripts
@@ -321,12 +323,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -689,6 +693,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    Pgbench executes test scripts chosen randomly from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1137,7 +1144,7 @@ number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
+SQL script 1, weight 1: &lt;builtin: TPC-B (sort of)&gt;
  - 10000 transactions (100.0% of total, tps = 618.764555)
  - latency average = 15.844 ms
  - latency stddev = 2.715 ms
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 7eb6a2d..5d24768 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -179,6 +179,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@' /* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -299,11 +301,14 @@ typedef struct
 static struct
 {
 	const char *name;
+	int weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int  total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
@@ -389,9 +394,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add weighted buitin script (use \"-b list\"\n"
+		   "                           to display available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add weighted transaction script from FILENAME\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1238,10 +1243,17 @@ clientDone(CState *st, bool ok)
 static int
 chooseScript(TState *thread)
 {
+	int i = 0, w = 0, wc;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	wc = (int) getrand(thread, 0, total_weight - 1);
+	do {
+		w += sql_script[i++].weight;
+	} while (w <= wc);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2683,8 +2695,41 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/* Possiby truncate option and return weight */
+static int
+getWeight(char *option)
+{
+	char   *sep;
+	int		weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		char *s;
+		*sep++ = '\0';
+
+		/* check that the weight is a positive integer */
+		s = sep;
+		while ('0' <= *s && *s <= '9')
+			s++;
+		if (*s != '\0' || s == sep)
+		{
+			/* empty or any other char */
+			fprintf(stderr,
+					"weight for script \"%s\" must be an integer, got \"%s\"\n",
+					option, sep);
+			exit(1);
+		}
+
+		weight = atoi(sep);
+	}
+	else
+		weight = 1;
+
+	return weight;
+}
+
 static void
-addScript(const char *name, Command **commands)
+addScript(const char *name, Command **commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2699,6 +2744,7 @@ addScript(const char *name, Command **commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2791,9 +2837,9 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
+			printf("SQL script %d, weight %d: %s\n"
+				" - "INT64_FORMAT" transactions (%.1f%% of total, tps = %f)\n",
+				   i + 1, sql_script[i].weight, sql_script[i].name,
 				   sql_script[i].stats.cnt,
 				   100.0 * sql_script[i].stats.cnt / total->cnt,
 				   sql_script[i].stats.cnt / time_include);
@@ -2887,6 +2933,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
+	int			weight;
 	char	   *desc;
 
 	int			i;
@@ -3066,27 +3113,32 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
+				weight = getWeight(optarg);
 				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+						  process_builtin(findBuiltin(optarg, &desc), desc),
+						  weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'S':
 				addScript(desc,
 						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+										  desc),
+						  1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc,
 						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+										  desc),
+						  1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = getWeight(optarg);
+				addScript(optarg, process_file(optarg), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3225,11 +3277,16 @@ main(int argc, char **argv)
 	if (num_scripts == 0 && !is_init_mode)
 	{
 		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+				  process_builtin(findBuiltin("tpcb-like", &desc), desc),
+				  1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..1b28d55 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         With special name <literal>list</>, show the list of builtin scripts
@@ -321,12 +323,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -686,9 +690,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1137,7 +1145,7 @@ number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
+SQL script 1, weight 1: &lt;builtin: TPC-B (sort of)&gt;
  - 10000 transactions (100.0% of total, tps = 618.764555)
  - latency average = 15.844 ms
  - latency stddev = 2.715 ms
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 7eb6a2d..418f441 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -179,6 +180,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -299,11 +302,14 @@ typedef struct
 static struct
 {
 	const char *name;
+	int			weight;
 	Command   **commands;
-	StatsData stats;
+	StatsData	stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int	total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
@@ -389,9 +395,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1238,10 +1244,20 @@ clientDone(CState *st, bool ok)
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0,
+				w = 0,
+				wc;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	wc = (int) getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w += sql_script[i++].weight;
+	} while (w <= wc);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2683,8 +2699,56 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
 static void
-addScript(const char *name, Command **commands)
+addScript(const char *name, Command **commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2699,6 +2763,7 @@ addScript(const char *name, Command **commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2791,9 +2856,9 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
+			printf("SQL script %d, weight %d: %s\n"
 			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
+				   i + 1, sql_script[i].weight, sql_script[i].name,
 				   sql_script[i].stats.cnt,
 				   100.0 * sql_script[i].stats.cnt / total->cnt,
 				   sql_script[i].stats.cnt / time_include);
@@ -2887,6 +2952,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
+	int			weight;
 	char	   *desc;
 
 	int			i;
@@ -2935,6 +3001,8 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char	*script;
+
 		switch (c)
 		{
 			case 'i':
@@ -3066,27 +3134,29 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
+				weight = parseScriptWeight(optarg, &script);
 				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				  process_builtin(findBuiltin(script, &desc), desc), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'S':
 				addScript(desc,
 						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+										  desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
 				addScript(desc,
 						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+										  desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(script, process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3225,11 +3295,18 @@ main(int argc, char **argv)
 	if (num_scripts == 0 && !is_init_mode)
 	{
 		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+				  process_builtin(findBuiltin("tpcb-like", &desc), desc), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+	{
+		/* FIXME this can overflow */
+		total_weight += sql_script[i].weight;
+	}
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..780a520 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         With special name <literal>list</>, show the list of builtin scripts
@@ -321,12 +323,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -686,9 +690,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1135,12 +1143,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 7eb6a2d..da4f05c 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -179,6 +180,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -299,23 +302,26 @@ typedef struct
 static struct
 {
 	const char *name;
+	int			weight;
 	Command   **commands;
-	StatsData stats;
+	StatsData	stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
 	char	   *commands;		/* actual pgbench script */
-}
+} script_t;
 
-			builtin_script[] =
+#define N_BUILTIN 3
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -389,9 +395,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1235,13 +1241,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2597,6 +2613,7 @@ process_file(char *filename)
 	return my_commands;
 }
 
+/* process builtin script tb and return an array of its commands */
 static Command **
 process_builtin(const char *tb, const char *source)
 {
@@ -2652,6 +2669,7 @@ process_builtin(const char *tb, const char *source)
 	return my_commands;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
@@ -2663,8 +2681,9 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name", or fail if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i;
 
@@ -2672,10 +2691,7 @@ findBuiltin(const char *name, char **desc)
 	{
 		if (strncmp(builtin_script[i].name, name,
 					strlen(builtin_script[i].name)) == 0)
-		{
-			*desc = builtin_script[i].desc;
-			return builtin_script[i].commands;
-		}
+			return & builtin_script[i];
 	}
 
 	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
@@ -2683,8 +2699,57 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of script to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(const char *name, Command **commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2699,6 +2764,7 @@ addScript(const char *name, Command **commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2784,19 +2850,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].name,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2804,7 +2875,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2887,7 +2959,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -2935,6 +3007,9 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+		script_t	*bi;
+
 		switch (c)
 		{
 			case 'i':
@@ -3066,27 +3141,29 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				bi = findBuiltin(script);
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc),
+						  weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				bi = findBuiltin("select-only");
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				bi = findBuiltin("simple-update");
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(script, process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3224,12 +3301,25 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		script_t *bi = findBuiltin("tpcb-like");
+		addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+	{
+		total_weight += sql_script[i].weight;
+
+		/* detect overflow... */
+		if (total_weight < 0)
+		{
+			fprintf(stderr, "script weight overflow at script %d\n", i+1);
+			exit(1);
+		}
+	}
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 780a520..82e217a 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -271,6 +271,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only be an unambiguous
+        prefix of the builtin name, hence <literal>si</> would be enough to
+        select <literal>simple-update</>.
         With special name <literal>list</>, show the list of builtin scripts
         and exit immediately.
        </para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index da4f05c..e394c1d 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -2681,20 +2681,33 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name", or fail if not found */
+/* return commands for selected builtin script, if unambiguous */
 static script_t *
 findBuiltin(const char *name)
 {
-	int			i;
+	int			i, found = 0, len = strlen(name);
+	script_t   *script = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
-		if (strncmp(builtin_script[i].name, name,
-					strlen(builtin_script[i].name)) == 0)
-			return & builtin_script[i];
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			script = & builtin_script[i];
+			found++;
+		}
 	}
 
-	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	/* ok, unambiguous result */
+	if (found == 1)
+		return script;
+
+	/* error cases */
+	if (found == 0)
+		fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	else /* found > 1 */
+		fprintf(stderr,
+				"%d builtin scripts found for prefix \"%s\"\n", found, name);
+
 	listAvailableScripts();
 	exit(1);
 }

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..780a520 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         With special name <literal>list</>, show the list of builtin scripts
@@ -321,12 +323,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -686,9 +690,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1135,12 +1143,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 7eb6a2d..a73e289 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -179,6 +180,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -299,23 +302,26 @@ typedef struct
 static struct
 {
 	const char *name;
+	int			weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
 	char	   *commands;		/* actual pgbench script */
-}
+} script_t;
 
-			builtin_script[] =
+#define N_BUILTIN 3
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -389,9 +395,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1235,13 +1241,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2597,6 +2613,7 @@ process_file(char *filename)
 	return my_commands;
 }
 
+/* process builtin script tb and return an array of its commands */
 static Command **
 process_builtin(const char *tb, const char *source)
 {
@@ -2652,6 +2669,7 @@ process_builtin(const char *tb, const char *source)
 	return my_commands;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
@@ -2663,8 +2681,9 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name", or fail if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i;
 
@@ -2672,10 +2691,7 @@ findBuiltin(const char *name, char **desc)
 	{
 		if (strncmp(builtin_script[i].name, name,
 					strlen(builtin_script[i].name)) == 0)
-		{
-			*desc = builtin_script[i].desc;
-			return builtin_script[i].commands;
-		}
+			return & builtin_script[i];
 	}
 
 	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
@@ -2683,8 +2699,57 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of scripts to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(const char *name, Command **commands, int weight)
 {
 	if (commands == NULL)
 	{
@@ -2699,6 +2764,7 @@ addScript(const char *name, Command **commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2784,19 +2850,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].name,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2804,7 +2875,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2887,7 +2959,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -2935,6 +3007,9 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+		script_t	*bi;
+
 		switch (c)
 		{
 			case 'i':
@@ -3066,27 +3141,29 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				bi = findBuiltin(script);
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc),
+						  weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				bi = findBuiltin("select-only");
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				bi = findBuiltin("simple-update");
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(script, process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3224,12 +3301,17 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		script_t *bi = findBuiltin("tpcb-like");
+		addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		/* cannot overflow: weight is 32b, total_weight 64b */
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 780a520..82e217a 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -271,6 +271,9 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
         probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
+        The provided <replaceable>scriptname</> needs only be an unambiguous
+        prefix of the builtin name, hence <literal>si</> would be enough to
+        select <literal>simple-update</>.
         With special name <literal>list</>, show the list of builtin scripts
         and exit immediately.
        </para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index a73e289..547636c 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -2681,20 +2681,33 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name", or fail if not found */
+/* return builtin script "name" if unambiguous */
 static script_t *
 findBuiltin(const char *name)
 {
-	int			i;
+	int			i, found = 0, len = strlen(name);
+	script_t   *script = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
-		if (strncmp(builtin_script[i].name, name,
-					strlen(builtin_script[i].name)) == 0)
-			return & builtin_script[i];
+		if (strncmp(builtin_script[i].name, name, len) == 0)
+		{
+			script = & builtin_script[i];
+			found++;
+		}
 	}
 
-	fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	/* ok, unambiguous result */
+	if (found == 1)
+		return script;
+
+	/* error cases */
+	if (found == 0)
+		fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
+	else /* found > 1 */
+		fprintf(stderr,
+				"%d builtin scripts found for prefix \"%s\"\n", found, name);
+
 	listAvailableScripts();
 	exit(1);
 }

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index cc80b3f..dd3fb1d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         Unambiguous prefixes of builtin names are accepted.
@@ -322,12 +324,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -687,9 +691,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1194,12 +1202,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 8b0b17a..c131681 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -179,6 +180,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -300,23 +303,26 @@ typedef struct
 static struct
 {
 	const char *name;
+	int			weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
 	char	   *commands;		/* actual pgbench script */
-}
+} script_t;
 
-			builtin_script[] =
+#define N_BUILTIN 3
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -392,9 +398,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1312,13 +1318,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2680,6 +2696,7 @@ process_file(char *filename)
 	return my_commands;
 }
 
+/* process builtin script tb and return an array of its commands */
 static Command **
 process_builtin(const char *tb, const char *source)
 {
@@ -2735,6 +2752,7 @@ process_builtin(const char *tb, const char *source)
 	return my_commands;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
@@ -2746,28 +2764,27 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name" if unambiguous */
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name" if unambiguous, of fails if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i,
 				found = 0,
 				len = strlen(name);
-	char	   *commands = NULL;
+	script_t   *result = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
 		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
-			*desc = builtin_script[i].desc;
-			commands = builtin_script[i].commands;
+			result = & builtin_script[i];
 			found++;
 		}
 	}
 
 	/* ok, unambiguous result */
 	if (found == 1)
-		return commands;
+		return result;
 
 	/* error cases */
 	if (found == 0)
@@ -2780,8 +2797,57 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of scripts to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(const char *name, Command **commands, int weight)
 {
 	if (commands == NULL ||
 		commands[0] == NULL)
@@ -2797,6 +2863,7 @@ addScript(const char *name, Command **commands)
 	}
 
 	sql_script[num_scripts].name = name;
+	sql_script[num_scripts].weight = weight;
 	sql_script[num_scripts].commands = commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
@@ -2882,19 +2949,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].name,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2902,7 +2974,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2985,7 +3058,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -3033,6 +3106,9 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+		script_t	*bi;
+
 		switch (c)
 		{
 			case 'i':
@@ -3164,27 +3240,29 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				bi = findBuiltin(script);
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc),
+						  weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				bi = findBuiltin("select-only");
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				bi = findBuiltin("simple-update");
+				addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(script, process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3322,12 +3400,17 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		script_t *bi = findBuiltin("tpcb-like");
+		addScript(bi->desc, process_builtin(bi->commands, bi->desc), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		/* cannot overflow: weight is 32b, total_weight 64b */
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index cc80b3f..dd3fb1d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         Unambiguous prefixes of builtin names are accepted.
@@ -322,12 +324,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -687,9 +691,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1194,12 +1202,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 8b0b17a..973d411 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -179,6 +180,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -300,23 +303,27 @@ typedef struct
 static struct
 {
 	const char *name;
+	int			weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
-	char	   *commands;		/* actual pgbench script */
-}
+	char	   *script;			/* actual pgbench script */
+	Command   **commands; 		/* temporary intermediate holder */
+} script_t;
 
-			builtin_script[] =
+#define N_BUILTIN 3
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -334,7 +341,8 @@ static struct
 		"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
 		"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-		"END;\n"
+		"END;\n",
+		NULL
 	},
 	{
 		"simple-update",
@@ -350,14 +358,16 @@ static struct
 		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
 		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-		"END;\n"
+		"END;\n",
+		NULL
 	},
 	{
 		"select-only",
 		"<builtin: select only>",
 		"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 		"\\setrandom aid 1 :naccounts\n"
-		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n",
+		NULL
 	}
 };
 
@@ -392,9 +402,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1312,13 +1322,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2623,12 +2643,14 @@ read_line_from_file(FILE *fd)
  * Given a file name, read it and return the array of Commands contained
  * therein.  "-" means to read stdin.
  */
-static Command **
+static script_t *
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
+	/* temporary holder to pass 2 information to addScript*/
+	static script_t fs;
+
 	FILE	   *fd;
 	int			lineno,
 				index;
@@ -2636,7 +2658,8 @@ process_file(char *filename)
 	int			alloc_num;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	fs.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	fs.desc = filename;
 
 	if (strcmp(filename, "-") == 0)
 		fd = stdin;
@@ -2644,7 +2667,7 @@ process_file(char *filename)
 	{
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
-		pg_free(my_commands);
+		pg_free(fs.commands);
 		return NULL;
 	}
 
@@ -2664,35 +2687,36 @@ process_file(char *filename)
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		fs.commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			fs.commands = pg_realloc(fs.commands, sizeof(Command *) * alloc_num);
 		}
 	}
 	fclose(fd);
 
-	my_commands[index] = NULL;
+	fs.commands[index] = NULL;
 
-	return my_commands;
+	return &fs;
 }
 
-static Command **
-process_builtin(const char *tb, const char *source)
+/* process builtin script tb and return an array of its commands */
+static script_t *
+process_builtin(script_t * bi)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
 	int			lineno,
 				index;
 	char		buf[BUFSIZ];
 	int			alloc_num;
+	char	   *tb = bi->script;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	bi->commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
 	lineno = 0;
 	index = 0;
@@ -2702,6 +2726,7 @@ process_builtin(const char *tb, const char *source)
 		char	   *p;
 		Command    *command;
 
+		/* buffer overflow check? */
 		p = buf;
 		while (*tb && *tb != '\n')
 			*p++ = *tb++;
@@ -2716,25 +2741,27 @@ process_builtin(const char *tb, const char *source)
 
 		lineno += 1;
 
-		command = process_commands(buf, source, lineno);
+		command = process_commands(buf, bi->desc, lineno);
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		bi->commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			bi->commands =
+				pg_realloc(bi->commands, sizeof(Command *) * alloc_num);
 		}
 	}
 
-	my_commands[index] = NULL;
+	bi->commands[index] = NULL;
 
-	return my_commands;
+	return bi;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
@@ -2746,28 +2773,27 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name" if unambiguous */
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name" if unambiguous, of fails if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i,
 				found = 0,
 				len = strlen(name);
-	char	   *commands = NULL;
+	script_t   *result = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
 		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
-			*desc = builtin_script[i].desc;
-			commands = builtin_script[i].commands;
+			result = & builtin_script[i];
 			found++;
 		}
 	}
 
 	/* ok, unambiguous result */
 	if (found == 1)
-		return commands;
+		return result;
 
 	/* error cases */
 	if (found == 0)
@@ -2780,13 +2806,61 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of scripts to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(script_t *script, int weight)
 {
-	if (commands == NULL ||
-		commands[0] == NULL)
+	if (script->commands == NULL || script->commands[0] == NULL)
 	{
-		fprintf(stderr, "empty command list for script \"%s\"\n", name);
+		fprintf(stderr, "empty command list for script \"%s\"\n", script->desc);
 		exit(1);
 	}
 
@@ -2796,8 +2870,9 @@ addScript(const char *name, Command **commands)
 		exit(1);
 	}
 
-	sql_script[num_scripts].name = name;
-	sql_script[num_scripts].commands = commands;
+	sql_script[num_scripts].name = script->desc;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = script->commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
@@ -2882,19 +2957,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].name,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2902,7 +2982,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2985,7 +3066,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -3033,6 +3114,8 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+
 		switch (c)
 		{
 			case 'i':
@@ -3164,27 +3247,25 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_builtin(findBuiltin(script)), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("select-only")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("simple-update")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3322,12 +3403,16 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		addScript(process_builtin(findBuiltin("tpcb-like")), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		/* cannot overflow: weight is 32b, total_weight 64b */
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index cc80b3f..dd3fb1d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         Unambiguous prefixes of builtin names are accepted.
@@ -322,12 +324,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -687,9 +691,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1194,12 +1202,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 8b0b17a..d7af86e 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -179,6 +180,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -300,23 +303,27 @@ typedef struct
 static struct
 {
 	const char *name;
+	int			weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
-	char	   *commands;		/* actual pgbench script */
-}
+	char	   *script;			/* actual pgbench script */
+	Command   **commands; 		/* temporary intermediate holder */
+} script_t;
 
-			builtin_script[] =
+#define N_BUILTIN 3
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -334,7 +341,8 @@ static struct
 		"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
 		"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-		"END;\n"
+		"END;\n",
+		NULL
 	},
 	{
 		"simple-update",
@@ -350,14 +358,16 @@ static struct
 		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
 		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-		"END;\n"
+		"END;\n",
+		NULL
 	},
 	{
 		"select-only",
 		"<builtin: select only>",
 		"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 		"\\setrandom aid 1 :naccounts\n"
-		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n",
+		NULL
 	}
 };
 
@@ -392,9 +402,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1312,13 +1322,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2620,15 +2640,17 @@ read_line_from_file(FILE *fd)
 }
 
 /*
- * Given a file name, read it and return the array of Commands contained
- * therein.  "-" means to read stdin.
+ * Given a file name, read it and return a script_t with a description &
+ * an array of commands.  "-" means to read stdin.
  */
-static Command **
+static script_t *
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
+	/* temporary holder to pass 2 information to addScript*/
+	static script_t fs;
+
 	FILE	   *fd;
 	int			lineno,
 				index;
@@ -2636,7 +2658,8 @@ process_file(char *filename)
 	int			alloc_num;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	fs.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	fs.desc = filename;
 
 	if (strcmp(filename, "-") == 0)
 		fd = stdin;
@@ -2644,7 +2667,7 @@ process_file(char *filename)
 	{
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
-		pg_free(my_commands);
+		pg_free(fs.commands);
 		return NULL;
 	}
 
@@ -2664,35 +2687,36 @@ process_file(char *filename)
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		fs.commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			fs.commands = pg_realloc(fs.commands, sizeof(Command *) * alloc_num);
 		}
 	}
 	fclose(fd);
 
-	my_commands[index] = NULL;
+	fs.commands[index] = NULL;
 
-	return my_commands;
+	return &fs;
 }
 
-static Command **
-process_builtin(const char *tb, const char *source)
+/* process builtin script bi by adding the array of commands and returning it */
+static script_t *
+process_builtin(script_t * bi)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
 	int			lineno,
 				index;
 	char		buf[BUFSIZ];
 	int			alloc_num;
+	char	   *tb = bi->script;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	bi->commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
 	lineno = 0;
 	index = 0;
@@ -2702,6 +2726,7 @@ process_builtin(const char *tb, const char *source)
 		char	   *p;
 		Command    *command;
 
+		/* buffer overflow check? */
 		p = buf;
 		while (*tb && *tb != '\n')
 			*p++ = *tb++;
@@ -2716,25 +2741,27 @@ process_builtin(const char *tb, const char *source)
 
 		lineno += 1;
 
-		command = process_commands(buf, source, lineno);
+		command = process_commands(buf, bi->desc, lineno);
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		bi->commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			bi->commands =
+				pg_realloc(bi->commands, sizeof(Command *) * alloc_num);
 		}
 	}
 
-	my_commands[index] = NULL;
+	bi->commands[index] = NULL;
 
-	return my_commands;
+	return bi;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
@@ -2746,28 +2773,27 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name" if unambiguous */
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name" if unambiguous, of fails if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i,
 				found = 0,
 				len = strlen(name);
-	char	   *commands = NULL;
+	script_t   *result = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
 		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
-			*desc = builtin_script[i].desc;
-			commands = builtin_script[i].commands;
+			result = & builtin_script[i];
 			found++;
 		}
 	}
 
 	/* ok, unambiguous result */
 	if (found == 1)
-		return commands;
+		return result;
 
 	/* error cases */
 	if (found == 0)
@@ -2780,13 +2806,61 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of scripts to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(script_t *script, int weight)
 {
-	if (commands == NULL ||
-		commands[0] == NULL)
+	if (script->commands == NULL || script->commands[0] == NULL)
 	{
-		fprintf(stderr, "empty command list for script \"%s\"\n", name);
+		fprintf(stderr, "empty command list for script \"%s\"\n", script->desc);
 		exit(1);
 	}
 
@@ -2796,8 +2870,9 @@ addScript(const char *name, Command **commands)
 		exit(1);
 	}
 
-	sql_script[num_scripts].name = name;
-	sql_script[num_scripts].commands = commands;
+	sql_script[num_scripts].name = script->desc;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = script->commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
@@ -2882,19 +2957,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].name,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2902,7 +2982,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2985,7 +3066,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -3033,6 +3114,8 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+
 		switch (c)
 		{
 			case 'i':
@@ -3164,27 +3247,25 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_builtin(findBuiltin(script)), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("select-only")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("simple-update")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3322,12 +3403,16 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		addScript(process_builtin(findBuiltin("tpcb-like")), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		/* cannot overflow: weight is 32b, total_weight 64b */
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index cc80b3f..dd3fb1d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         Unambiguous prefixes of builtin names are accepted.
@@ -322,12 +324,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -687,9 +691,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1194,12 +1202,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 8b0b17a..5363648 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -179,6 +180,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -300,23 +303,27 @@ typedef struct
 static struct
 {
 	const char *name;
+	int			weight;
 	Command   **commands;
 	StatsData stats;
 }	sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
-	char	   *commands;		/* actual pgbench script */
-}
+	char	   *script;			/* actual pgbench script */
+	Command   **commands; 		/* temporary intermediate holder */
+} script_t;
 
-			builtin_script[] =
+#define N_BUILTIN 3
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -334,7 +341,8 @@ static struct
 		"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
 		"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
 		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-		"END;\n"
+		"END;\n",
+		NULL
 	},
 	{
 		"simple-update",
@@ -350,14 +358,16 @@ static struct
 		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
 		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
 		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
-		"END;\n"
+		"END;\n",
+		NULL
 	},
 	{
 		"select-only",
 		"<builtin: select only>",
 		"\\set naccounts " CppAsString2(naccounts) " * :scale\n"
 		"\\setrandom aid 1 :naccounts\n"
-		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
+		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n",
+		NULL
 	}
 };
 
@@ -392,9 +402,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1312,13 +1322,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -2620,15 +2640,17 @@ read_line_from_file(FILE *fd)
 }
 
 /*
- * Given a file name, read it and return the array of Commands contained
- * therein.  "-" means to read stdin.
+ * Given a file name, read it and return a script_t with a description &
+ * an array of commands.  "-" means to read stdin.
  */
-static Command **
+static script_t *
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
+	/* very small memory leak, does not matter */
+	script_t * fs = pg_malloc(sizeof(script_t));
+
 	FILE	   *fd;
 	int			lineno,
 				index;
@@ -2636,7 +2658,8 @@ process_file(char *filename)
 	int			alloc_num;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	fs->commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	fs->desc = filename;
 
 	if (strcmp(filename, "-") == 0)
 		fd = stdin;
@@ -2644,7 +2667,7 @@ process_file(char *filename)
 	{
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
-		pg_free(my_commands);
+		pg_free(fs->commands);
 		return NULL;
 	}
 
@@ -2664,35 +2687,37 @@ process_file(char *filename)
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		fs->commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			fs->commands = pg_realloc(fs->commands,
+									  sizeof(Command *) * alloc_num);
 		}
 	}
 	fclose(fd);
 
-	my_commands[index] = NULL;
+	fs->commands[index] = NULL;
 
-	return my_commands;
+	return fs;
 }
 
-static Command **
-process_builtin(const char *tb, const char *source)
+/* process builtin script bi by adding the array of commands and returning it */
+static script_t *
+process_builtin(script_t * bi)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
 	int			lineno,
 				index;
 	char		buf[BUFSIZ];
 	int			alloc_num;
+	char	   *tb = bi->script;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	bi->commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
 	lineno = 0;
 	index = 0;
@@ -2702,6 +2727,7 @@ process_builtin(const char *tb, const char *source)
 		char	   *p;
 		Command    *command;
 
+		/* buffer overflow check? */
 		p = buf;
 		while (*tb && *tb != '\n')
 			*p++ = *tb++;
@@ -2716,25 +2742,27 @@ process_builtin(const char *tb, const char *source)
 
 		lineno += 1;
 
-		command = process_commands(buf, source, lineno);
+		command = process_commands(buf, bi->desc, lineno);
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		bi->commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			bi->commands =
+				pg_realloc(bi->commands, sizeof(Command *) * alloc_num);
 		}
 	}
 
-	my_commands[index] = NULL;
+	bi->commands[index] = NULL;
 
-	return my_commands;
+	return bi;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
@@ -2746,28 +2774,27 @@ listAvailableScripts(void)
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name" if unambiguous */
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name" if unambiguous, of fails if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i,
 				found = 0,
 				len = strlen(name);
-	char	   *commands = NULL;
+	script_t   *result = NULL;
 
 	for (i = 0; i < N_BUILTIN; i++)
 	{
 		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
-			*desc = builtin_script[i].desc;
-			commands = builtin_script[i].commands;
+			result = & builtin_script[i];
 			found++;
 		}
 	}
 
 	/* ok, unambiguous result */
 	if (found == 1)
-		return commands;
+		return result;
 
 	/* error cases */
 	if (found == 0)
@@ -2780,13 +2807,61 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of scripts to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(script_t *script, int weight)
 {
-	if (commands == NULL ||
-		commands[0] == NULL)
+	if (script->commands == NULL || script->commands[0] == NULL)
 	{
-		fprintf(stderr, "empty command list for script \"%s\"\n", name);
+		fprintf(stderr, "empty command list for script \"%s\"\n", script->desc);
 		exit(1);
 	}
 
@@ -2796,8 +2871,9 @@ addScript(const char *name, Command **commands)
 		exit(1);
 	}
 
-	sql_script[num_scripts].name = name;
-	sql_script[num_scripts].commands = commands;
+	sql_script[num_scripts].name = script->desc;
+	sql_script[num_scripts].weight = weight;
+	sql_script[num_scripts].commands = script->commands;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
@@ -2882,19 +2958,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].name,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2902,7 +2983,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2985,7 +3067,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -3033,6 +3115,8 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+
 		switch (c)
 		{
 			case 'i':
@@ -3164,27 +3248,25 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_builtin(findBuiltin(script)), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("select-only")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("simple-update")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3322,12 +3404,16 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		addScript(process_builtin(findBuiltin("tpcb-like")), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		/* cannot overflow: weight is 32b, total_weight 64b */
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index cc80b3f..dd3fb1d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         Unambiguous prefixes of builtin names are accepted.
@@ -322,12 +324,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -687,9 +691,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1194,12 +1202,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 5a3c6cd..04deb2c 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -180,6 +181,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -298,26 +301,30 @@ typedef struct
 	SimpleStats stats;			/* time spent in this command */
 } Command;
 
-static struct
+typedef struct
 {
-	const char *name;
+	const char *desc;
+	int			weight;
 	Command   **commands;
-	StatsData stats;
-}	sql_script[MAX_SCRIPTS];	/* SQL script files */
+	StatsData	stats;
+} ParsedScript;
+
+static ParsedScript sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
-	char	   *commands;		/* actual pgbench script */
-}
+	char	   *script;			/* actual pgbench script */
+} script_t;
 
-			builtin_script[] =
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -393,9 +400,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1313,13 +1320,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -1493,7 +1510,7 @@ top:
 			commands = sql_script[st->use_file].commands;
 			if (debug)
 				fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
-						sql_script[st->use_file].name);
+						sql_script[st->use_file].desc);
 			st->is_throttled = false;
 
 			/*
@@ -2625,34 +2642,36 @@ read_line_from_file(FILE *fd)
 }
 
 /*
- * Given a file name, read it and return the array of Commands contained
- * therein.  "-" means to read stdin.
+ * Given a file name, read it and return a script_t with a description &
+ * an array of commands.  "-" means to read stdin.
  */
-static Command **
+static ParsedScript *
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
+	ParsedScript * ps;
+
 	FILE	   *fd;
 	int			lineno,
 				index;
 	char	   *buf;
 	int			alloc_num;
 
-	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
-
 	if (strcmp(filename, "-") == 0)
 		fd = stdin;
 	else if ((fd = fopen(filename, "r")) == NULL)
 	{
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
-		pg_free(my_commands);
 		return NULL;
 	}
 
+	alloc_num = COMMANDS_ALLOC_NUM;
+	ps = pg_malloc(sizeof(ParsedScript));
+	ps->commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	ps->desc = filename;
+
 	lineno = 0;
 	index = 0;
 
@@ -2669,35 +2688,40 @@ process_file(char *filename)
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		ps->commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			ps->commands = pg_realloc(ps->commands,
+									  sizeof(Command *) * alloc_num);
 		}
 	}
 	fclose(fd);
 
-	my_commands[index] = NULL;
+	ps->commands[index] = NULL;
 
-	return my_commands;
+	return ps;
 }
 
-static Command **
-process_builtin(const char *tb, const char *source)
+/* process builtin script bi by adding the array of commands and returning it */
+static ParsedScript *
+process_builtin(script_t * bi)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
 	int			lineno,
 				index;
 	char		buf[BUFSIZ];
 	int			alloc_num;
+	char	   *tb = bi->script;
+	ParsedScript *ps;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	ps = (ParsedScript *) pg_malloc(sizeof(ParsedScript));
+	ps->desc = bi->desc;
+	ps->commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
 	lineno = 0;
 	index = 0;
@@ -2707,6 +2731,7 @@ process_builtin(const char *tb, const char *source)
 		char	   *p;
 		Command    *command;
 
+		/* buffer overflow check? */
 		p = buf;
 		while (*tb && *tb != '\n')
 			*p++ = *tb++;
@@ -2721,58 +2746,59 @@ process_builtin(const char *tb, const char *source)
 
 		lineno += 1;
 
-		command = process_commands(buf, source, lineno);
+		command = process_commands(buf, bi->desc, lineno);
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		ps->commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			ps->commands =
+				pg_realloc(ps->commands, sizeof(Command *) * alloc_num);
 		}
 	}
 
-	my_commands[index] = NULL;
+	ps->commands[index] = NULL;
 
-	return my_commands;
+	return ps;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
 	int			i;
 
 	fprintf(stderr, "Available builtin scripts:\n");
-	for (i = 0; i < N_BUILTIN; i++)
+	for (i = 0; i < lengthof(builtin_script); i++)
 		fprintf(stderr, "\t%s\n", builtin_script[i].name);
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name" if unambiguous */
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name" if unambiguous, of fails if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i,
 				found = 0,
 				len = strlen(name);
-	char	   *commands = NULL;
+	script_t   *result = NULL;
 
-	for (i = 0; i < N_BUILTIN; i++)
+	for (i = 0; i < lengthof(builtin_script); i++)
 	{
 		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
-			*desc = builtin_script[i].desc;
-			commands = builtin_script[i].commands;
+			result = & builtin_script[i];
 			found++;
 		}
 	}
 
 	/* ok, unambiguous result */
 	if (found == 1)
-		return commands;
+		return result;
 
 	/* error cases */
 	if (found == 0)
@@ -2785,13 +2811,61 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of scripts to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(ParsedScript *script, int weight)
 {
-	if (commands == NULL ||
-		commands[0] == NULL)
+	if (script->commands == NULL || script->commands[0] == NULL)
 	{
-		fprintf(stderr, "empty command list for script \"%s\"\n", name);
+		fprintf(stderr, "empty command list for script \"%s\"\n", script->desc);
 		exit(1);
 	}
 
@@ -2801,10 +2875,13 @@ addScript(const char *name, Command **commands)
 		exit(1);
 	}
 
-	sql_script[num_scripts].name = name;
-	sql_script[num_scripts].commands = commands;
+	sql_script[num_scripts] = *script;
+	sql_script[num_scripts].weight = weight;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
+
+	/* was allocated in process_builtin or process_file */
+	free(script);
 }
 
 static void
@@ -2833,7 +2910,7 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
 	printf("transaction type: %s\n",
-		   num_scripts == 1 ? sql_script[0].name : "multiple scripts");
+		   num_scripts == 1 ? sql_script[0].desc : "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2887,19 +2964,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].desc,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2907,7 +2989,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2990,7 +3073,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -3038,6 +3121,8 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+
 		switch (c)
 		{
 			case 'i':
@@ -3169,27 +3254,25 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_builtin(findBuiltin(script)), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("select-only")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("simple-update")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3327,12 +3410,16 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		addScript(process_builtin(findBuiltin("tpcb-like")), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		/* cannot overflow: weight is 32b, total_weight 64b */
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;
@@ -3738,7 +3825,7 @@ threadRun(void *arg)
 		commands = sql_script[st->use_file].commands;
 		if (debug)
 			fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
-					sql_script[st->use_file].name);
+					sql_script[st->use_file].desc);
 		if (!doCustom(thread, st, &aggs))
 			remains--;			/* I've aborted */
 

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index cc80b3f..dd3fb1d 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -262,11 +262,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
 
     <variablelist>
      <varlistentry>
-      <term><option>-b</> <replaceable>scriptname</></term>
-      <term><option>--builtin</> <replaceable>scriptname</></term>
+      <term><option>-b</> <replaceable>scriptname[@weight]</></term>
+      <term><option>--builtin</>=<replaceable>scriptname[@weight]</></term>
       <listitem>
        <para>
         Add the specified builtin script to the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the script.  If not specified, it is set to 1.
         Available builtin scripts are: <literal>tpcb-like</>,
         <literal>simple-update</> and <literal>select-only</>.
         Unambiguous prefixes of builtin names are accepted.
@@ -322,12 +324,14 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
      </varlistentry>
 
      <varlistentry>
-      <term><option>-f</> <replaceable>filename</></term>
-      <term><option>--file=</><replaceable>filename</></term>
+      <term><option>-f</> <replaceable>filename[@weight]</></term>
+      <term><option>--file=</><replaceable>filename[@weight]</></term>
       <listitem>
        <para>
         Add a transaction script read from <replaceable>filename</> to
         the list of executed scripts.
+        An optional integer weight after <literal>@</> allows to adjust the
+        probability of drawing the test.
         See below for details.
        </para>
       </listitem>
@@ -687,9 +691,13 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
   <title>What is the <quote>Transaction</> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
-   Pgbench executes test scripts chosen randomly from a specified list.
+   <application>pgbench</> executes test scripts chosen randomly
+   from a specified list.
    They include built-in scripts with <option>-b</> and
    user-provided custom scripts with <option>-f</>.
+   Each script may be given a relative weight specified after a
+   <literal>@</> so as to change its drawing probability.
+   The default weight is <literal>1</>.
  </para>
 
   <para>
@@ -1194,12 +1202,11 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
+latency average = 15.844 ms
+latency stddev = 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
-SQL script 1: &lt;builtin: TPC-B (sort of)&gt;
- - 10000 transactions (100.0% of total, tps = 618.764555)
- - latency average = 15.844 ms
- - latency stddev = 2.715 ms
+script statistics:
  - statement latencies in milliseconds:
         0.004386        \set nbranches 1 * :scale
         0.001343        \set ntellers 10 * :scale
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 5a3c6cd..a32db2b 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -38,6 +38,7 @@
 #include "portability/instr_time.h"
 
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 #include <signal.h>
 #include <sys/time.h>
@@ -180,6 +181,8 @@ char	   *login = NULL;
 char	   *dbName;
 const char *progname;
 
+#define WSEP '@'				/* weight separator */
+
 volatile bool timer_exceeded = false;	/* flag from signal handler */
 
 /* variable definitions */
@@ -298,26 +301,30 @@ typedef struct
 	SimpleStats stats;			/* time spent in this command */
 } Command;
 
-static struct
+typedef struct
 {
-	const char *name;
+	const char *desc;
+	int			weight;
 	Command   **commands;
-	StatsData stats;
-}	sql_script[MAX_SCRIPTS];	/* SQL script files */
+	StatsData	stats;
+} ParsedScript;
+
+static ParsedScript sql_script[MAX_SCRIPTS];	/* SQL script files */
 static int	num_scripts;		/* number of scripts in sql_script[] */
 static int	num_commands = 0;	/* total number of Command structs */
+static int64 total_weight = 0;
+
 static int	debug = 0;			/* debug flag */
 
 /* Define builtin test scripts */
-#define N_BUILTIN 3
-static struct
+typedef struct script_t
 {
 	char	   *name;			/* very short name for -b ... */
 	char	   *desc;			/* short description */
-	char	   *commands;		/* actual pgbench script */
-}
+	char	   *script;			/* actual pgbench script */
+} script_t;
 
-			builtin_script[] =
+static script_t builtin_script[] =
 {
 	{
 		"tpcb-like",
@@ -393,9 +400,9 @@ usage(void)
 	 "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
 		   "  --unlogged-tables        create tables as unlogged tables\n"
 		   "\nOptions to select what to run:\n"
-		   "  -b, --builtin=NAME       add buitin script (use \"-b list\" to display\n"
-		   "                           available scripts)\n"
-		   "  -f, --file=FILENAME      add transaction script from FILENAME\n"
+		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
+		   "                           (use \"-b list\" to list available scripts)\n"
+		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
 		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
 		   "                           (same as \"-b simple-update\")\n"
 		   "  -S, --select-only        perform SELECT-only transactions\n"
@@ -1313,13 +1320,23 @@ clientDone(CState *st, bool ok)
 	return false;				/* always false */
 }
 
+/* return a script number with a weighted choice. */
 static int
 chooseScript(TState *thread)
 {
+	int			i = 0;
+	int64		w;
+
 	if (num_scripts == 1)
 		return 0;
 
-	return getrand(thread, 0, num_scripts - 1);
+	w = getrand(thread, 0, total_weight - 1);
+	do
+	{
+		w -= sql_script[i++].weight;
+	} while (w >= 0);
+
+	return i - 1;
 }
 
 /* return false iff client should be disconnected */
@@ -1493,7 +1510,7 @@ top:
 			commands = sql_script[st->use_file].commands;
 			if (debug)
 				fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
-						sql_script[st->use_file].name);
+						sql_script[st->use_file].desc);
 			st->is_throttled = false;
 
 			/*
@@ -2625,34 +2642,35 @@ read_line_from_file(FILE *fd)
 }
 
 /*
- * Given a file name, read it and return the array of Commands contained
- * therein.  "-" means to read stdin.
+ * Given a file name, read it and return a script_t with a description &
+ * an array of commands.  "-" means to read stdin.
  */
-static Command **
+static ParsedScript
 process_file(char *filename)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
+	ParsedScript ps;
+
 	FILE	   *fd;
 	int			lineno,
 				index;
 	char	   *buf;
 	int			alloc_num;
 
-	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
-
 	if (strcmp(filename, "-") == 0)
 		fd = stdin;
 	else if ((fd = fopen(filename, "r")) == NULL)
 	{
 		fprintf(stderr, "could not open file \"%s\": %s\n",
 				filename, strerror(errno));
-		pg_free(my_commands);
-		return NULL;
+		exit(1);
 	}
 
+	alloc_num = COMMANDS_ALLOC_NUM;
+	ps.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	ps.desc = filename;
+
 	lineno = 0;
 	index = 0;
 
@@ -2669,35 +2687,38 @@ process_file(char *filename)
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		ps.commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			ps.commands = pg_realloc(ps.commands, sizeof(Command *) * alloc_num);
 		}
 	}
 	fclose(fd);
 
-	my_commands[index] = NULL;
+	ps.commands[index] = NULL;
 
-	return my_commands;
+	return ps;
 }
 
-static Command **
-process_builtin(const char *tb, const char *source)
+/* process builtin script bi by adding the array of commands and returning it */
+static ParsedScript
+process_builtin(script_t * bi)
 {
 #define COMMANDS_ALLOC_NUM 128
 
-	Command   **my_commands;
 	int			lineno,
 				index;
 	char		buf[BUFSIZ];
 	int			alloc_num;
+	char	   *tb = bi->script;
+	ParsedScript ps;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	my_commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	ps.desc = bi->desc;
+	ps.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
 
 	lineno = 0;
 	index = 0;
@@ -2707,6 +2728,7 @@ process_builtin(const char *tb, const char *source)
 		char	   *p;
 		Command    *command;
 
+		/* buffer overflow check? */
 		p = buf;
 		while (*tb && *tb != '\n')
 			*p++ = *tb++;
@@ -2721,58 +2743,58 @@ process_builtin(const char *tb, const char *source)
 
 		lineno += 1;
 
-		command = process_commands(buf, source, lineno);
+		command = process_commands(buf, bi->desc, lineno);
 		if (command == NULL)
 			continue;
 
-		my_commands[index] = command;
+		ps.commands[index] = command;
 		index++;
 
 		if (index >= alloc_num)
 		{
 			alloc_num += COMMANDS_ALLOC_NUM;
-			my_commands = pg_realloc(my_commands, sizeof(Command *) * alloc_num);
+			ps.commands = pg_realloc(ps.commands, sizeof(Command *) * alloc_num);
 		}
 	}
 
-	my_commands[index] = NULL;
+	ps.commands[index] = NULL;
 
-	return my_commands;
+	return ps;
 }
 
+/* show available builtin scripts */
 static void
 listAvailableScripts(void)
 {
 	int			i;
 
 	fprintf(stderr, "Available builtin scripts:\n");
-	for (i = 0; i < N_BUILTIN; i++)
+	for (i = 0; i < lengthof(builtin_script); i++)
 		fprintf(stderr, "\t%s\n", builtin_script[i].name);
 	fprintf(stderr, "\n");
 }
 
-/* return builtin script "name" if unambiguous */
-static char *
-findBuiltin(const char *name, char **desc)
+/* return builtin script "name" if unambiguous, of fails if not found */
+static script_t *
+findBuiltin(const char *name)
 {
 	int			i,
 				found = 0,
 				len = strlen(name);
-	char	   *commands = NULL;
+	script_t   *result = NULL;
 
-	for (i = 0; i < N_BUILTIN; i++)
+	for (i = 0; i < lengthof(builtin_script); i++)
 	{
 		if (strncmp(builtin_script[i].name, name, len) == 0)
 		{
-			*desc = builtin_script[i].desc;
-			commands = builtin_script[i].commands;
+			result = & builtin_script[i];
 			found++;
 		}
 	}
 
 	/* ok, unambiguous result */
 	if (found == 1)
-		return commands;
+		return result;
 
 	/* error cases */
 	if (found == 0)
@@ -2785,13 +2807,61 @@ findBuiltin(const char *name, char **desc)
 	exit(1);
 }
 
+/*
+ * Determine the weight specification from a script option (-b, -f), if any,
+ * and return it as an integer (1 is returned if there's no weight).  The
+ * script name is returned in *script as a malloc'd string.
+ */
+static int
+parseScriptWeight(const char *option, char **script)
+{
+	char	   *sep;
+	int			weight;
+
+	if ((sep = strrchr(option, WSEP)))
+	{
+		int		namelen = sep - option;
+		long	wtmp;
+		char   *badp;
+
+		/* generate the script name */
+		*script = pg_malloc(namelen + 1);
+		strncpy(*script, option, namelen);
+		(*script)[namelen] = '\0';
+
+		/* process digits of the weight spec */
+		errno = 0;
+		wtmp = strtol(sep + 1, &badp, 10);
+		if (errno != 0 || badp == sep + 1 || *badp != '\0')
+		{
+			fprintf(stderr, "invalid weight specification: %s\n", sep);
+			exit(1);
+		}
+		if (wtmp > INT_MAX || wtmp <= 0)
+		{
+			fprintf(stderr,
+					"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+					INT_MAX, (int64) wtmp);
+			exit(1);
+		}
+		weight = wtmp;
+	}
+	else
+	{
+		*script = pg_strdup(option);
+		weight = 1;
+	}
+
+	return weight;
+}
+
+/* append a script to the list of scripts to process */
 static void
-addScript(const char *name, Command **commands)
+addScript(ParsedScript script, int weight)
 {
-	if (commands == NULL ||
-		commands[0] == NULL)
+	if (script.commands == NULL || script.commands[0] == NULL)
 	{
-		fprintf(stderr, "empty command list for script \"%s\"\n", name);
+		fprintf(stderr, "empty command list for script \"%s\"\n", script.desc);
 		exit(1);
 	}
 
@@ -2801,8 +2871,8 @@ addScript(const char *name, Command **commands)
 		exit(1);
 	}
 
-	sql_script[num_scripts].name = name;
-	sql_script[num_scripts].commands = commands;
+	sql_script[num_scripts] = script;
+	sql_script[num_scripts].weight = weight;
 	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
@@ -2833,7 +2903,7 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 						(INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
 
 	printf("transaction type: %s\n",
-		   num_scripts == 1 ? sql_script[0].name : "multiple scripts");
+		   num_scripts == 1 ? sql_script[0].desc : "multiple scripts");
 	printf("scaling factor: %d\n", scale);
 	printf("query mode: %s\n", QUERYMODE[querymode]);
 	printf("number of clients: %d\n", nclients);
@@ -2887,19 +2957,24 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	printf("tps = %f (including connections establishing)\n", tps_include);
 	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
 
-	/* Report per-command statistics */
-	if (per_script_stats)
+	/* Report per-script/command statistics */
+	if (per_script_stats || latency_limit || is_latencies)
 	{
 		int			i;
 
 		for (i = 0; i < num_scripts; i++)
 		{
-			printf("SQL script %d: %s\n"
-			" - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
-				   i + 1, sql_script[i].name,
-				   sql_script[i].stats.cnt,
-				   100.0 * sql_script[i].stats.cnt / total->cnt,
-				   sql_script[i].stats.cnt / time_include);
+			if (num_scripts > 1)
+				printf("SQL script %d: %s\n"
+					   " - weight = %d\n"
+					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
+					   i + 1, sql_script[i].desc,
+					   sql_script[i].weight,
+					   sql_script[i].stats.cnt,
+					   100.0 * sql_script[i].stats.cnt / total->cnt,
+					   sql_script[i].stats.cnt / time_include);
+			else
+				printf("script statistics:\n");
 
 			if (latency_limit)
 				printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
@@ -2907,7 +2982,8 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 					   100.0 * sql_script[i].stats.skipped /
 					(sql_script[i].stats.skipped + sql_script[i].stats.cnt));
 
-			printSimpleStats(" - latency", &sql_script[i].stats.latency);
+			if (num_scripts > 1)
+				printSimpleStats(" - latency", &sql_script[i].stats.latency);
 
 			/* Report per-command latencies */
 			if (is_latencies)
@@ -2990,7 +3066,7 @@ main(int argc, char **argv)
 	instr_time	conn_total_time;
 	int64		latency_late = 0;
 	StatsData	stats;
-	char	   *desc;
+	int			weight;
 
 	int			i;
 	int			nclients_dealt;
@@ -3038,6 +3114,8 @@ main(int argc, char **argv)
 
 	while ((c = getopt_long(argc, argv, "ih:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
 	{
+		char		*script;
+
 		switch (c)
 		{
 			case 'i':
@@ -3169,27 +3247,25 @@ main(int argc, char **argv)
 					exit(0);
 				}
 
-				addScript(desc,
-						  process_builtin(findBuiltin(optarg, &desc), desc));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_builtin(findBuiltin(script)), weight);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
+
 			case 'S':
-				addScript(desc,
-						  process_builtin(findBuiltin("select-only", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("select-only")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(desc,
-						  process_builtin(findBuiltin("simple-update", &desc),
-										  desc));
+				addScript(process_builtin(findBuiltin("simple-update")), 1);
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
-				addScript(optarg, process_file(optarg));
+				weight = parseScriptWeight(optarg, &script);
+				addScript(process_file(script), weight);
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3327,12 +3403,16 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(desc,
-				  process_builtin(findBuiltin("tpcb-like", &desc), desc));
+		addScript(process_builtin(findBuiltin("tpcb-like")), 1);
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}
 
+	/* compute total_weight */
+	for (i = 0; i < num_scripts; i++)
+		/* cannot overflow: weight is 32b, total_weight 64b */
+		total_weight += sql_script[i].weight;
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;
@@ -3738,7 +3818,7 @@ threadRun(void *arg)
 		commands = sql_script[st->use_file].commands;
 		if (debug)
 			fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
-					sql_script[st->use_file].name);
+					sql_script[st->use_file].desc);
 		if (!doCustom(thread, st, &aggs))
 			remains--;			/* I've aborted */
 

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index ecabff0..4606fb0 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -2649,11 +2649,23 @@ read_line_from_file(FILE *fd)
 }
 
 /*
+ * Initialize a ParsedScript
+ */
+static void
+initParsedScript(ParsedScript *ps, const char *desc, int alloc_num, int weight)
+{
+	ps->commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	ps->desc = desc;
+	ps->weight = weight;
+	initStats(&ps->stats, 0.0);
+}
+
+/*
  * Given a file name, read it and return its ParsedScript representation.  "-"
  * means to read stdin.
  */
 static ParsedScript
-process_file(char *filename)
+process_file(char *filename, int weight)
 {
 #define COMMANDS_ALLOC_NUM 128
 	ParsedScript ps;
@@ -2673,8 +2685,7 @@ process_file(char *filename)
 	}
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	ps.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
-	ps.desc = filename;
+	initParsedScript(&ps, filename, alloc_num, weight);
 
 	lineno = 0;
 	index = 0;
@@ -2710,7 +2721,7 @@ process_file(char *filename)
 
 /* Parse the given builtin script and return the parsed representation */
 static ParsedScript
-process_builtin(BuiltinScript *bi)
+process_builtin(BuiltinScript *bi, int weight)
 {
 	int			lineno,
 				index;
@@ -2720,8 +2731,7 @@ process_builtin(BuiltinScript *bi)
 	ParsedScript ps;
 
 	alloc_num = COMMANDS_ALLOC_NUM;
-	ps.desc = bi->desc;
-	ps.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
+	initParsedScript(&ps, bi->desc, alloc_num, weight);
 
 	lineno = 0;
 	index = 0;
@@ -2860,7 +2870,7 @@ parseScriptWeight(const char *option, char **script)
 
 /* append a script to the list of scripts to process */
 static void
-addScript(ParsedScript script, int weight)
+addScript(ParsedScript script)
 {
 	if (script.commands == NULL || script.commands[0] == NULL)
 	{
@@ -2875,8 +2885,6 @@ addScript(ParsedScript script, int weight)
 	}
 
 	sql_script[num_scripts] = script;
-	sql_script[num_scripts].weight = weight;
-	initStats(&sql_script[num_scripts].stats, 0.0);
 	num_scripts++;
 }
 
@@ -3251,24 +3259,24 @@ main(int argc, char **argv)
 				}
 
 				weight = parseScriptWeight(optarg, &script);
-				addScript(process_builtin(findBuiltin(script)), weight);
+				addScript(process_builtin(findBuiltin(script), weight));
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 
 			case 'S':
-				addScript(process_builtin(findBuiltin("select-only")), 1);
+				addScript(process_builtin(findBuiltin("select-only"), 1));
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'N':
-				addScript(process_builtin(findBuiltin("simple-update")), 1);
+				addScript(process_builtin(findBuiltin("simple-update"), 1));
 				benchmarking_option_set = true;
 				internal_script_used = true;
 				break;
 			case 'f':
 				weight = parseScriptWeight(optarg, &script);
-				addScript(process_file(script), weight);
+				addScript(process_file(script, weight));
 				benchmarking_option_set = true;
 				break;
 			case 'D':
@@ -3406,7 +3414,7 @@ main(int argc, char **argv)
 	/* set default script if none */
 	if (num_scripts == 0 && !is_init_mode)
 	{
-		addScript(process_builtin(findBuiltin("tpcb-like")), 1);
+		addScript(process_builtin(findBuiltin("tpcb-like"), 1));
 		benchmarking_option_set = true;
 		internal_script_used = true;
 	}

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
new file mode 100644
index dab1ed4..e8c1906
*** a/src/bin/pgbench/pgbench.c
--- b/src/bin/pgbench/pgbench.c
*************** parseScriptWeight(const char *option, ch
*** 2855,2864 ****
  			fprintf(stderr, "invalid weight specification: %s\n", sep);
  			exit(1);
  		}
! 		if (wtmp > INT_MAX || wtmp <= 0)
  		{
  			fprintf(stderr,
! 			"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
  					INT_MAX, (int64) wtmp);
  			exit(1);
  		}
--- 2855,2864 ----
  			fprintf(stderr, "invalid weight specification: %s\n", sep);
  			exit(1);
  		}
! 		if (wtmp > INT_MAX || wtmp < 0)
  		{
  			fprintf(stderr,
! 			"weight specification out of range (0 .. %u): " INT64_FORMAT "\n",
  					INT_MAX, (int64) wtmp);
  			exit(1);
  		}
*************** main(int argc, char **argv)
*** 3429,3434 ****
--- 3429,3440 ----
  		/* cannot overflow: weight is 32b, total_weight 64b */
  		total_weight += sql_script[i].weight;
  
+ 	if (total_weight == 0)
+ 	{
+ 		fprintf(stderr, "The total of script weights (from -b and -f options) cannot be zero.\n");
+ 		exit(1);
+ 	}
+ 
  	/* show per script stats if several scripts are used */
  	if (num_scripts > 1)
  		per_script_stats = true;

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index c6d1454..e31d5ee 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -698,6 +698,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
    Each script may be given a relative weight specified after a
    <literal>@</> so as to change its drawing probability.
    The default weight is <literal>1</>.
+   Weight <literal>0</> scripts are ignored.
  </para>
 
   <para>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 4196b0e..0c1a0ee 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -2953,10 +2953,10 @@ parseScriptWeight(const char *option, char **script)
 			fprintf(stderr, "invalid weight specification: %s\n", sep);
 			exit(1);
 		}
-		if (wtmp > INT_MAX || wtmp <= 0)
+		if (wtmp > INT_MAX || wtmp < 0)
 		{
 			fprintf(stderr,
-			"weight specification out of range (1 .. %u): " INT64_FORMAT "\n",
+			"weight specification out of range (0 .. %u): " INT64_FORMAT "\n",
 					INT_MAX, (int64) wtmp);
 			exit(1);
 		}
@@ -2987,6 +2987,13 @@ addScript(ParsedScript script)
 		exit(1);
 	}
 
+	if (script.weight == 0)
+	{
+		fprintf(stderr,
+				"warning, script \"%s\" (%d) weight is zero, will be ignored\n",
+				script.desc, num_scripts);
+	}
+
 	sql_script[num_scripts] = script;
 	num_scripts++;
 }
@@ -3527,6 +3534,12 @@ main(int argc, char **argv)
 		/* cannot overflow: weight is 32b, total_weight 64b */
 		total_weight += sql_script[i].weight;
 
+	if (total_weight == 0)
+	{
+		fprintf(stderr, "total weight for scripts (-b and -f options) cannot be zero\n");
+		exit(1);
+	}
+
 	/* show per script stats if several scripts are used */
 	if (num_scripts > 1)
 		per_script_stats = true;

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 52d1223..5cb5906 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3152,10 +3152,13 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 
 	if (throttle_delay || progress || latency_limit)
 		printSimpleStats("latency", &total->latency);
-	else
+	else if (duration > 0)
 		/* only an average latency computed from the duration is available */
-		printf("latency average: %.3f ms\n",
+		printf("latency average: %.3f ms",
 			   1000.0 * duration * nclients / total->cnt);
+	else
+		printf("latency average: %.3f ms",
+			   1000.0 * time_include * nclients / total->cnt);
 
 	if (throttle_delay)
 	{

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 06cd5db..297af4f 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1253,8 +1253,8 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
-latency average = 15.844 ms
-latency stddev = 2.715 ms
+latency average: 15.844 ms
+latency stddev: 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
 script statistics:
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 52d1223..d5380d2 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3099,8 +3099,8 @@ printSimpleStats(char *prefix, SimpleStats *ss)
 	double		latency = ss->sum / ss->count;
 	double		stddev = sqrt(ss->sum2 / ss->count - latency * latency);
 
-	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
-	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+	printf("%s average: %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev: %.3f ms\n", prefix, 0.001 * stddev);
 }
 
 /* print out results */
@@ -3155,7 +3155,7 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	else
 		/* only an average latency computed from the duration is available */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / total->cnt);
+			   1000.0 * time_include * nclients / total->cnt);
 
 	if (throttle_delay)
 	{