pgbench - extend initialization phase control

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 816f9cc4c7..bcdac60ade 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -167,7 +167,7 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
         <replaceable>init_steps</replaceable> specifies the
         initialization steps to be performed, using one character per step.
         Each step is invoked in the specified order.
-        The default is <literal>dtgvp</literal>.
+        The default is <literal>dt(g)vp</literal>.
         The available steps are:
 
         <variablelist>
@@ -193,12 +193,31 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
           </listitem>
          </varlistentry>
          <varlistentry>
-          <term><literal>g</literal> (Generate data)</term>
+          <term><literal>(</literal> (begin transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>BEGIN</command>.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>g</literal> or <literal>G</literal> (Generate data, client or server side)</term>
           <listitem>
            <para>
             Generate data and load it into the standard tables,
             replacing any data already present.
            </para>
+           <para>
+            When data is generated server side, there is no progress output.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>)</literal> (commit transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>COMMIT</command>.
+           </para>
           </listitem>
          </varlistentry>
          <varlistentry>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 570cf3306a..a990eb6f21 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -130,7 +130,13 @@ static int	pthread_join(pthread_t th, void **thread_return);
 /********************************************************************
  * some configurable parameters */
 
-#define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
+/*
+ * we do all data generation in one transaction to enable the backend's
+ * data-loading optimizations
+ */
+#define DEFAULT_INIT_STEPS "dt(g)vp"	/* default -I setting */
+
+#define ALL_INIT_STEPS "dtgGvpf()"		/* all possible steps */
 
 #define LOG_STEP_SECONDS	5	/* seconds between log messages */
 #define DEFAULT_NXACTS	10		/* default nxacts */
@@ -608,7 +614,7 @@ usage(void)
 		   "  %s [OPTION]... [DBNAME]\n"
 		   "\nInitialization options:\n"
 		   "  -i, --initialize         invokes initialization mode\n"
-		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
+		   "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
 		   "                           run selected initialization steps\n"
 		   "  -F, --fillfactor=NUM     set fill factor\n"
 		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
@@ -3689,10 +3695,23 @@ initCreateTables(PGconn *con)
 }
 
 /*
- * Fill the standard tables with some data
+ * truncate away any old data, in one command in case there are foreign keys
  */
 static void
-initGenerateData(PGconn *con)
+initTruncateTables(PGconn *con)
+{
+	executeStatement(con, "truncate table "
+					 "pgbench_accounts, "
+					 "pgbench_branches, "
+					 "pgbench_history, "
+					 "pgbench_tellers");
+}
+
+/*
+ * Fill the standard tables with some data, from the client side
+ */
+static void
+initGenerateDataClientSide(PGconn *con)
 {
 	char		sql[256];
 	PGresult   *res;
@@ -3706,23 +3725,9 @@ initGenerateData(PGconn *con)
 				remaining_sec;
 	int			log_interval = 1;
 
-	fprintf(stderr, "generating data...\n");
+	fprintf(stderr, "generating data client side...\n");
 
-	/*
-	 * we do all of this in one transaction to enable the backend's
-	 * data-loading optimizations
-	 */
-	executeStatement(con, "begin");
-
-	/*
-	 * truncate away any old data, in one command in case there are foreign
-	 * keys
-	 */
-	executeStatement(con, "truncate table "
-					 "pgbench_accounts, "
-					 "pgbench_branches, "
-					 "pgbench_history, "
-					 "pgbench_tellers");
+	initTruncateTables(con);
 
 	/*
 	 * fill branches, tellers, accounts in that order in case foreign keys
@@ -3822,8 +3827,37 @@ initGenerateData(PGconn *con)
 		fprintf(stderr, "PQendcopy failed\n");
 		exit(1);
 	}
+}
 
-	executeStatement(con, "commit");
+/*
+ * Fill the standard tables with some data, from the server side
+ */
+static void
+initGenerateDataServerSide(PGconn *con)
+{
+	char		sql[256];
+
+	fprintf(stderr, "generating data server side...\n");
+
+	initTruncateTables(con);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_branches(bid,bbalance,filler) "
+			 "select bid, 0, '' "
+			 "from generate_series(1, %d) as bid", scale);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_tellers(tid,bid,tbalance,filler) "
+			 "select tid, (tid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, %d) as tid", ntellers, scale * ntellers);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_accounts(aid,bid,abalance,filler) "
+			 "select aid, (aid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, %d) as aid", naccounts, scale * naccounts);
+	executeStatement(con, sql);
 }
 
 /*
@@ -3907,6 +3941,7 @@ static void
 checkInitSteps(const char *initialize_steps)
 {
 	const char *step;
+	int begins = 0;
 
 	if (initialize_steps[0] == '\0')
 	{
@@ -3916,13 +3951,40 @@ checkInitSteps(const char *initialize_steps)
 
 	for (step = initialize_steps; *step != '\0'; step++)
 	{
-		if (strchr("dtgvpf ", *step) == NULL)
+		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
 		{
-			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
+			fprintf(stderr,
+					"unrecognized initialization step \"%c\"\n"
+					"allowed step characters are: \"" ALL_INIT_STEPS "\"\n",
 					*step);
-			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
 			exit(1);
 		}
+
+		/* count BEGIN/COMMIT for matching */
+		if (*step == '(')
+			begins++;
+		else if (*step == ')')
+			begins--;
+
+		if (begins < 0)
+		{
+			fprintf(stderr, "COMMIT \")\" at char %ld of \"%s\" does not have a matching BEGIN \"(\"\n",
+							step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+		else if (begins >= 2)
+		{
+			fprintf(stderr, "BEGIN \"(\" within a BEGIN at char %ld of \"%s\", nested transactions are not supported\n",
+					step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+	}
+
+	if (begins > 0)
+	{
+		fprintf(stderr, "a BEGIN \"(\" in \"%s\" does not have a matching COMMIT \")\"\n",
+						initialize_steps);
+		exit(1);
 	}
 }
 
@@ -3960,9 +4022,20 @@ runInitSteps(const char *initialize_steps)
 				op = "create tables";
 				initCreateTables(con);
 				break;
+			case '(':
+				executeStatement(con, "begin");
+				break;
 			case 'g':
-				op = "generate";
-				initGenerateData(con);
+				op = "client generate";
+				initGenerateDataClientSide(con);
+				break;
+			case 'G':
+				op = "server generate";
+				initGenerateDataServerSide(con);
+				break;
+			case ')':
+				op = "commit";
+				executeStatement(con, "commit");
 				break;
 			case 'v':
 				op = "vacuum";
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index 5a2fdb9acb..9cbbfb9245 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -100,7 +100,7 @@ pgbench(
 
 # Again, with all possible options
 pgbench(
-	'--initialize --init-steps=dtpvg --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=pg_default --index-tablespace=pg_default',
+	'--initialize --init-steps=dtpv(g) --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=pg_default --index-tablespace=pg_default',
 	0,
 	[qr{^$}i],
 	[
@@ -116,14 +116,14 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables',
+	'--initialize --init-steps=dtpv(G)vv --no-vacuum --foreign-keys --unlogged-tables',
 	0,
 	[qr{^$}],
 	[
 		qr{dropping old tables},
 		qr{creating tables},
 		qr{creating primary keys},
-		qr{.* of .* tuples \(.*\) done},
+		qr{generating data server side},
 		qr{creating foreign keys},
 		qr{(?!vacuuming)}, # no vacuum
 		qr{done in \d+\.\d\d s }
diff --git a/src/bin/pgbench/t/002_pgbench_no_server.pl b/src/bin/pgbench/t/002_pgbench_no_server.pl
index f7fa18418b..f3406e8600 100644
--- a/src/bin/pgbench/t/002_pgbench_no_server.pl
+++ b/src/bin/pgbench/t/002_pgbench_no_server.pl
@@ -147,7 +147,22 @@ my @options = (
 	[
 		'invalid init step',
 		'-i -I dta',
-		[ qr{unrecognized initialization step}, qr{allowed steps are} ]
+		[ qr{unrecognized initialization step}, qr{allowed step characters are} ]
+	],
+	[
+		'invalid init step begin/begin',
+		'-i -I ((',
+		[ qr{nested transactions are not supported} ]
+	],
+	[
+		'invalid init step end',
+		'-i -I )',
+		[ qr{does not have a matching BEGIN} ]
+	],
+	[
+		'invalid init step begin',
+		'-i -I (dt',
+		[ qr{does not have a matching COMMIT} ]
 	],
 	[
 		'bad random seed',

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index e3a0abb4c7..e9f43f3b26 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -167,7 +167,7 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
         <replaceable>init_steps</replaceable> specifies the
         initialization steps to be performed, using one character per step.
         Each step is invoked in the specified order.
-        The default is <literal>dtgvp</literal>.
+        The default is <literal>dt(g)vp</literal>.
         The available steps are:
 
         <variablelist>
@@ -193,12 +193,31 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
           </listitem>
          </varlistentry>
          <varlistentry>
-          <term><literal>g</literal> (Generate data)</term>
+          <term><literal>(</literal> (begin transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>BEGIN</command>.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>g</literal> or <literal>G</literal> (Generate data, client or server side)</term>
           <listitem>
            <para>
             Generate data and load it into the standard tables,
             replacing any data already present.
            </para>
+           <para>
+            When data is generated server side, there is no progress output.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>)</literal> (commit transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>COMMIT</command>.
+           </para>
           </listitem>
          </varlistentry>
          <varlistentry>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e72ad0036e..50b8139f50 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -130,7 +130,13 @@ static int	pthread_join(pthread_t th, void **thread_return);
 /********************************************************************
  * some configurable parameters */
 
-#define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
+/*
+ * we do all data generation in one transaction to enable the backend's
+ * data-loading optimizations
+ */
+#define DEFAULT_INIT_STEPS "dt(g)vp"	/* default -I setting */
+
+#define ALL_INIT_STEPS "dtgGvpf()"		/* all possible steps */
 
 #define LOG_STEP_SECONDS	5	/* seconds between log messages */
 #define DEFAULT_NXACTS	10		/* default nxacts */
@@ -626,7 +632,7 @@ usage(void)
 		   "  %s [OPTION]... [DBNAME]\n"
 		   "\nInitialization options:\n"
 		   "  -i, --initialize         invokes initialization mode\n"
-		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
+		   "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
 		   "                           run selected initialization steps\n"
 		   "  -F, --fillfactor=NUM     set fill factor\n"
 		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
@@ -3802,10 +3808,23 @@ append_fillfactor(char *opts, int len)
 }
 
 /*
- * Fill the standard tables with some data
+ * truncate away any old data, in one command in case there are foreign keys
  */
 static void
-initGenerateData(PGconn *con)
+initTruncateTables(PGconn *con)
+{
+	executeStatement(con, "truncate table "
+					 "pgbench_accounts, "
+					 "pgbench_branches, "
+					 "pgbench_history, "
+					 "pgbench_tellers");
+}
+
+/*
+ * Fill the standard tables with some data, from the client side
+ */
+static void
+initGenerateDataClientSide(PGconn *con)
 {
 	char		sql[256];
 	PGresult   *res;
@@ -3819,23 +3838,9 @@ initGenerateData(PGconn *con)
 				remaining_sec;
 	int			log_interval = 1;
 
-	fprintf(stderr, "generating data...\n");
+	fprintf(stderr, "generating data client side...\n");
 
-	/*
-	 * we do all of this in one transaction to enable the backend's
-	 * data-loading optimizations
-	 */
-	executeStatement(con, "begin");
-
-	/*
-	 * truncate away any old data, in one command in case there are foreign
-	 * keys
-	 */
-	executeStatement(con, "truncate table "
-					 "pgbench_accounts, "
-					 "pgbench_branches, "
-					 "pgbench_history, "
-					 "pgbench_tellers");
+	initTruncateTables(con);
 
 	/*
 	 * fill branches, tellers, accounts in that order in case foreign keys
@@ -3935,8 +3940,37 @@ initGenerateData(PGconn *con)
 		fprintf(stderr, "PQendcopy failed\n");
 		exit(1);
 	}
+}
 
-	executeStatement(con, "commit");
+/*
+ * Fill the standard tables with some data, from the server side
+ */
+static void
+initGenerateDataServerSide(PGconn *con)
+{
+	char		sql[256];
+
+	fprintf(stderr, "generating data server side...\n");
+
+	initTruncateTables(con);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_branches(bid,bbalance,filler) "
+			 "select bid, 0, '' "
+			 "from generate_series(1, %d) as bid", scale);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_tellers(tid,bid,tbalance,filler) "
+			 "select tid, (tid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, %d) as tid", ntellers, scale * ntellers);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_accounts(aid,bid,abalance,filler) "
+			 "select aid, (aid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, %d) as aid", naccounts, scale * naccounts);
+	executeStatement(con, sql);
 }
 
 /*
@@ -4020,6 +4054,7 @@ static void
 checkInitSteps(const char *initialize_steps)
 {
 	const char *step;
+	int begins = 0;
 
 	if (initialize_steps[0] == '\0')
 	{
@@ -4029,13 +4064,40 @@ checkInitSteps(const char *initialize_steps)
 
 	for (step = initialize_steps; *step != '\0'; step++)
 	{
-		if (strchr("dtgvpf ", *step) == NULL)
+		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
 		{
-			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
+			fprintf(stderr,
+					"unrecognized initialization step \"%c\"\n"
+					"Allowed step characters are: \"" ALL_INIT_STEPS "\".\n",
 					*step);
-			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
 			exit(1);
 		}
+
+		/* count BEGIN/COMMIT for matching */
+		if (*step == '(')
+			begins++;
+		else if (*step == ')')
+			begins--;
+
+		if (begins < 0)
+		{
+			fprintf(stderr, "COMMIT \")\" at char %ld of \"%s\" does not have a matching BEGIN \"(\"\n",
+							step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+		else if (begins >= 2)
+		{
+			fprintf(stderr, "BEGIN \"(\" within a BEGIN at char %ld of \"%s\", nested transactions are not supported\n",
+					step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+	}
+
+	if (begins > 0)
+	{
+		fprintf(stderr, "a BEGIN \"(\" in \"%s\" does not have a matching COMMIT \")\"\n",
+						initialize_steps);
+		exit(1);
 	}
 }
 
@@ -4073,9 +4135,20 @@ runInitSteps(const char *initialize_steps)
 				op = "create tables";
 				initCreateTables(con);
 				break;
+			case '(':
+				executeStatement(con, "begin");
+				break;
 			case 'g':
-				op = "generate";
-				initGenerateData(con);
+				op = "client generate";
+				initGenerateDataClientSide(con);
+				break;
+			case 'G':
+				op = "server generate";
+				initGenerateDataServerSide(con);
+				break;
+			case ')':
+				op = "commit";
+				executeStatement(con, "commit");
 				break;
 			case 'v':
 				op = "vacuum";
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index c441626d7c..ddfdc79efa 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -113,7 +113,7 @@ pgbench(
 
 # Again, with all possible options
 pgbench(
-	'--initialize --init-steps=dtpvg --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=regress_pgbench_tap_1_ts --index-tablespace=regress_pgbench_tap_1_ts --partitions=2 --partition-method=hash',
+	'--initialize --init-steps=dtpv(g) --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=regress_pgbench_tap_1_ts --index-tablespace=regress_pgbench_tap_1_ts --partitions=2 --partition-method=hash',
 	0,
 	[qr{^$}i],
 	[
@@ -130,7 +130,7 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
+	'--initialize --init-steps=dtpv(G)vv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
 	0,
 	[qr{^$}],
 	[
@@ -138,7 +138,7 @@ pgbench(
 		qr{creating tables},
 		qr{creating 3 partitions},
 		qr{creating primary keys},
-		qr{.* of .* tuples \(.*\) done},
+		qr{generating data server side},
 		qr{creating foreign keys},
 		qr{(?!vacuuming)}, # no vacuum
 		qr{done in \d+\.\d\d s }
diff --git a/src/bin/pgbench/t/002_pgbench_no_server.pl b/src/bin/pgbench/t/002_pgbench_no_server.pl
index 1e9542af3f..256c7104cd 100644
--- a/src/bin/pgbench/t/002_pgbench_no_server.pl
+++ b/src/bin/pgbench/t/002_pgbench_no_server.pl
@@ -147,7 +147,22 @@ my @options = (
 	[
 		'invalid init step',
 		'-i -I dta',
-		[ qr{unrecognized initialization step}, qr{allowed steps are} ]
+		[ qr{unrecognized initialization step}, qr{allowed step characters are} ]
+	],
+	[
+		'invalid init step begin/begin',
+		'-i -I ((',
+		[ qr{nested transactions are not supported} ]
+	],
+	[
+		'invalid init step end',
+		'-i -I )',
+		[ qr{does not have a matching BEGIN} ]
+	],
+	[
+		'invalid init step begin',
+		'-i -I (dt',
+		[ qr{does not have a matching COMMIT} ]
 	],
 	[
 		'bad random seed',

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index e3a0abb4c7..c5e4d17fd5 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -167,7 +167,7 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
         <replaceable>init_steps</replaceable> specifies the
         initialization steps to be performed, using one character per step.
         Each step is invoked in the specified order.
-        The default is <literal>dtgvp</literal>.
+        The default is <literal>dt(g)vp</literal>.
         The available steps are:
 
         <variablelist>
@@ -193,12 +193,40 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
           </listitem>
          </varlistentry>
          <varlistentry>
-          <term><literal>g</literal> (Generate data)</term>
+          <term><literal>(</literal> (begin transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>BEGIN</command>.
+           </para>
+           <para>
+            Beware that some steps may not work when called within an explicit transaction.
+           </para>
+           <para>
+            Beware that using <literal>(</literal> on the command line requires some protection or escaping.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>g</literal> or <literal>G</literal> (Generate data, client or server side)</term>
           <listitem>
            <para>
             Generate data and load it into the standard tables,
             replacing any data already present.
            </para>
+           <para>
+            When data is generated server side, there is no progress output.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>)</literal> (commit transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>COMMIT</command>.
+           </para>
+           <para>
+            Beware that using <literal>)</literal> on the command line requires some protection or escaping.
+           </para>
           </listitem>
          </varlistentry>
          <varlistentry>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e72ad0036e..597562248a 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -130,7 +130,13 @@ static int	pthread_join(pthread_t th, void **thread_return);
 /********************************************************************
  * some configurable parameters */
 
-#define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
+/*
+ * we do all data generation in one transaction to enable the backend's
+ * data-loading optimizations
+ */
+#define DEFAULT_INIT_STEPS "dt(g)vp"	/* default -I setting */
+
+#define ALL_INIT_STEPS "dtgGvpf()"		/* all possible steps */
 
 #define LOG_STEP_SECONDS	5	/* seconds between log messages */
 #define DEFAULT_NXACTS	10		/* default nxacts */
@@ -626,7 +632,7 @@ usage(void)
 		   "  %s [OPTION]... [DBNAME]\n"
 		   "\nInitialization options:\n"
 		   "  -i, --initialize         invokes initialization mode\n"
-		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
+		   "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
 		   "                           run selected initialization steps\n"
 		   "  -F, --fillfactor=NUM     set fill factor\n"
 		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
@@ -3802,10 +3808,23 @@ append_fillfactor(char *opts, int len)
 }
 
 /*
- * Fill the standard tables with some data
+ * truncate away any old data, in one command in case there are foreign keys
  */
 static void
-initGenerateData(PGconn *con)
+initTruncateTables(PGconn *con)
+{
+	executeStatement(con, "truncate table "
+					 "pgbench_accounts, "
+					 "pgbench_branches, "
+					 "pgbench_history, "
+					 "pgbench_tellers");
+}
+
+/*
+ * Fill the standard tables with some data, from the client side
+ */
+static void
+initGenerateDataClientSide(PGconn *con)
 {
 	char		sql[256];
 	PGresult   *res;
@@ -3819,23 +3838,9 @@ initGenerateData(PGconn *con)
 				remaining_sec;
 	int			log_interval = 1;
 
-	fprintf(stderr, "generating data...\n");
+	fprintf(stderr, "generating data client side...\n");
 
-	/*
-	 * we do all of this in one transaction to enable the backend's
-	 * data-loading optimizations
-	 */
-	executeStatement(con, "begin");
-
-	/*
-	 * truncate away any old data, in one command in case there are foreign
-	 * keys
-	 */
-	executeStatement(con, "truncate table "
-					 "pgbench_accounts, "
-					 "pgbench_branches, "
-					 "pgbench_history, "
-					 "pgbench_tellers");
+	initTruncateTables(con);
 
 	/*
 	 * fill branches, tellers, accounts in that order in case foreign keys
@@ -3935,8 +3940,41 @@ initGenerateData(PGconn *con)
 		fprintf(stderr, "PQendcopy failed\n");
 		exit(1);
 	}
+}
 
-	executeStatement(con, "commit");
+/*
+ * Fill the standard tables with some data, from the server side
+ *
+ * As already the case with the client-side filling, the filler
+ * column defaults to NULL in pgbench_branches and pgbench_tellers,
+ * and is a blank-padded string in pgbench_accounts.
+ */
+static void
+initGenerateDataServerSide(PGconn *con)
+{
+	char		sql[256];
+
+	fprintf(stderr, "generating data server side...\n");
+
+	initTruncateTables(con);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_branches(bid,bbalance) "
+			 "select bid, 0 "
+			 "from generate_series(1, %d) as bid", scale);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_tellers(tid,bid,tbalance) "
+			 "select tid, (tid - 1) / %d + 1, 0 "
+			 "from generate_series(1, %d) as tid", ntellers, scale * ntellers);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_accounts(aid,bid,abalance,filler) "
+			 "select aid, (aid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, %d) as aid", naccounts, scale * naccounts);
+	executeStatement(con, sql);
 }
 
 /*
@@ -4020,6 +4058,7 @@ static void
 checkInitSteps(const char *initialize_steps)
 {
 	const char *step;
+	int begins = 0;
 
 	if (initialize_steps[0] == '\0')
 	{
@@ -4029,13 +4068,40 @@ checkInitSteps(const char *initialize_steps)
 
 	for (step = initialize_steps; *step != '\0'; step++)
 	{
-		if (strchr("dtgvpf ", *step) == NULL)
+		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
 		{
-			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
+			fprintf(stderr,
+					"unrecognized initialization step \"%c\"\n"
+					"Allowed step characters are: \"" ALL_INIT_STEPS "\".\n",
 					*step);
-			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
 			exit(1);
 		}
+
+		/* count BEGIN/COMMIT for matching */
+		if (*step == '(')
+			begins++;
+		else if (*step == ')')
+			begins--;
+
+		if (begins < 0)
+		{
+			fprintf(stderr, "COMMIT \")\" at char %ld of \"%s\" does not have a matching BEGIN \"(\"\n",
+							step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+		else if (begins >= 2)
+		{
+			fprintf(stderr, "BEGIN \"(\" within a BEGIN at char %ld of \"%s\", nested transactions are not supported\n",
+					step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+	}
+
+	if (begins > 0)
+	{
+		fprintf(stderr, "a BEGIN \"(\" in \"%s\" does not have a matching COMMIT \")\"\n",
+						initialize_steps);
+		exit(1);
 	}
 }
 
@@ -4073,9 +4139,20 @@ runInitSteps(const char *initialize_steps)
 				op = "create tables";
 				initCreateTables(con);
 				break;
+			case '(':
+				executeStatement(con, "begin");
+				break;
 			case 'g':
-				op = "generate";
-				initGenerateData(con);
+				op = "client generate";
+				initGenerateDataClientSide(con);
+				break;
+			case 'G':
+				op = "server generate";
+				initGenerateDataServerSide(con);
+				break;
+			case ')':
+				op = "commit";
+				executeStatement(con, "commit");
 				break;
 			case 'v':
 				op = "vacuum";
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index c441626d7c..ddfdc79efa 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -113,7 +113,7 @@ pgbench(
 
 # Again, with all possible options
 pgbench(
-	'--initialize --init-steps=dtpvg --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=regress_pgbench_tap_1_ts --index-tablespace=regress_pgbench_tap_1_ts --partitions=2 --partition-method=hash',
+	'--initialize --init-steps=dtpv(g) --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=regress_pgbench_tap_1_ts --index-tablespace=regress_pgbench_tap_1_ts --partitions=2 --partition-method=hash',
 	0,
 	[qr{^$}i],
 	[
@@ -130,7 +130,7 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
+	'--initialize --init-steps=dtpv(G)vv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
 	0,
 	[qr{^$}],
 	[
@@ -138,7 +138,7 @@ pgbench(
 		qr{creating tables},
 		qr{creating 3 partitions},
 		qr{creating primary keys},
-		qr{.* of .* tuples \(.*\) done},
+		qr{generating data server side},
 		qr{creating foreign keys},
 		qr{(?!vacuuming)}, # no vacuum
 		qr{done in \d+\.\d\d s }
diff --git a/src/bin/pgbench/t/002_pgbench_no_server.pl b/src/bin/pgbench/t/002_pgbench_no_server.pl
index 1e9542af3f..39badeb3aa 100644
--- a/src/bin/pgbench/t/002_pgbench_no_server.pl
+++ b/src/bin/pgbench/t/002_pgbench_no_server.pl
@@ -147,7 +147,22 @@ my @options = (
 	[
 		'invalid init step',
 		'-i -I dta',
-		[ qr{unrecognized initialization step}, qr{allowed steps are} ]
+		[ qr{unrecognized initialization step}, qr{Allowed step characters are} ]
+	],
+	[
+		'invalid init step begin/begin',
+		'-i -I ((',
+		[ qr{nested transactions are not supported} ]
+	],
+	[
+		'invalid init step end',
+		'-i -I )',
+		[ qr{does not have a matching BEGIN} ]
+	],
+	[
+		'invalid init step begin',
+		'-i -I (dt',
+		[ qr{does not have a matching COMMIT} ]
 	],
 	[
 		'bad random seed',

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index e3a0abb4c7..e150209b4e 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -167,7 +167,7 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
         <replaceable>init_steps</replaceable> specifies the
         initialization steps to be performed, using one character per step.
         Each step is invoked in the specified order.
-        The default is <literal>dtgvp</literal>.
+        The default is <literal>dt{g}vp</literal>.
         The available steps are:
 
         <variablelist>
@@ -193,12 +193,34 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
           </listitem>
          </varlistentry>
          <varlistentry>
-          <term><literal>g</literal> (Generate data)</term>
+          <term><literal>{</literal> (begin transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>BEGIN</command>.
+           </para>
+           <para>
+            Beware that some steps may not work when called within an explicit transaction.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>g</literal> or <literal>G</literal> (Generate data, client or server side)</term>
           <listitem>
            <para>
             Generate data and load it into the standard tables,
             replacing any data already present.
            </para>
+           <para>
+            When data is generated server side, there is no progress output.
+           </para>
+          </listitem>
+         </varlistentry>
+         <varlistentry>
+          <term><literal>}</literal> (commit transaction)</term>
+          <listitem>
+           <para>
+            Emit a <command>COMMIT</command>.
+           </para>
           </listitem>
          </varlistentry>
          <varlistentry>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e72ad0036e..be10630926 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -130,7 +130,13 @@ static int	pthread_join(pthread_t th, void **thread_return);
 /********************************************************************
  * some configurable parameters */
 
-#define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
+/*
+ * we do all data generation in one transaction to enable the backend's
+ * data-loading optimizations
+ */
+#define DEFAULT_INIT_STEPS "dt{g}vp"	/* default -I setting */
+
+#define ALL_INIT_STEPS "dtgGvpf{}"		/* all possible steps */
 
 #define LOG_STEP_SECONDS	5	/* seconds between log messages */
 #define DEFAULT_NXACTS	10		/* default nxacts */
@@ -626,7 +632,7 @@ usage(void)
 		   "  %s [OPTION]... [DBNAME]\n"
 		   "\nInitialization options:\n"
 		   "  -i, --initialize         invokes initialization mode\n"
-		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
+		   "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
 		   "                           run selected initialization steps\n"
 		   "  -F, --fillfactor=NUM     set fill factor\n"
 		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
@@ -3802,10 +3808,23 @@ append_fillfactor(char *opts, int len)
 }
 
 /*
- * Fill the standard tables with some data
+ * truncate away any old data, in one command in case there are foreign keys
  */
 static void
-initGenerateData(PGconn *con)
+initTruncateTables(PGconn *con)
+{
+	executeStatement(con, "truncate table "
+					 "pgbench_accounts, "
+					 "pgbench_branches, "
+					 "pgbench_history, "
+					 "pgbench_tellers");
+}
+
+/*
+ * Fill the standard tables with some data, from the client side
+ */
+static void
+initGenerateDataClientSide(PGconn *con)
 {
 	char		sql[256];
 	PGresult   *res;
@@ -3819,23 +3838,9 @@ initGenerateData(PGconn *con)
 				remaining_sec;
 	int			log_interval = 1;
 
-	fprintf(stderr, "generating data...\n");
+	fprintf(stderr, "generating data client side...\n");
 
-	/*
-	 * we do all of this in one transaction to enable the backend's
-	 * data-loading optimizations
-	 */
-	executeStatement(con, "begin");
-
-	/*
-	 * truncate away any old data, in one command in case there are foreign
-	 * keys
-	 */
-	executeStatement(con, "truncate table "
-					 "pgbench_accounts, "
-					 "pgbench_branches, "
-					 "pgbench_history, "
-					 "pgbench_tellers");
+	initTruncateTables(con);
 
 	/*
 	 * fill branches, tellers, accounts in that order in case foreign keys
@@ -3935,8 +3940,41 @@ initGenerateData(PGconn *con)
 		fprintf(stderr, "PQendcopy failed\n");
 		exit(1);
 	}
+}
 
-	executeStatement(con, "commit");
+/*
+ * Fill the standard tables with some data, from the server side
+ *
+ * As already the case with the client-side filling, the filler
+ * column defaults to NULL in pgbench_branches and pgbench_tellers,
+ * and is a blank-padded string in pgbench_accounts.
+ */
+static void
+initGenerateDataServerSide(PGconn *con)
+{
+	char		sql[256];
+
+	fprintf(stderr, "generating data server side...\n");
+
+	initTruncateTables(con);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_branches(bid,bbalance) "
+			 "select bid, 0 "
+			 "from generate_series(1, %d) as bid", scale);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_tellers(tid,bid,tbalance) "
+			 "select tid, (tid - 1) / %d + 1, 0 "
+			 "from generate_series(1, %d) as tid", ntellers, scale * ntellers);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_accounts(aid,bid,abalance,filler) "
+			 "select aid, (aid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, %d) as aid", naccounts, scale * naccounts);
+	executeStatement(con, sql);
 }
 
 /*
@@ -4020,6 +4058,7 @@ static void
 checkInitSteps(const char *initialize_steps)
 {
 	const char *step;
+	int begins = 0;
 
 	if (initialize_steps[0] == '\0')
 	{
@@ -4029,13 +4068,46 @@ checkInitSteps(const char *initialize_steps)
 
 	for (step = initialize_steps; *step != '\0'; step++)
 	{
-		if (strchr("dtgvpf ", *step) == NULL)
+		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
 		{
-			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
+			fprintf(stderr,
+					"unrecognized initialization step \"%c\"\n"
+					"Allowed step characters are: \"" ALL_INIT_STEPS "\".\n",
 					*step);
-			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
 			exit(1);
 		}
+
+		if (*step == 'v' && begins > 0)
+		{
+			fprintf(stderr, "VACUUM cannot run inside a transaction block\n");
+			exit(1);
+		}
+
+		/* count BEGIN/COMMIT for matching */
+		if (*step == '{')
+			begins++;
+		else if (*step == '}')
+			begins--;
+
+		if (begins < 0)
+		{
+			fprintf(stderr, "COMMIT \"}\" at char %ld of \"%s\" does not have a matching BEGIN \"{\"\n",
+							step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+		else if (begins >= 2)
+		{
+			fprintf(stderr, "BEGIN \"{\" within a BEGIN at char %ld of \"%s\", nested transactions are not supported\n",
+					step - initialize_steps, initialize_steps);
+			exit(1);
+		}
+	}
+
+	if (begins > 0)
+	{
+		fprintf(stderr, "a BEGIN \"{\" in \"%s\" does not have a matching COMMIT \"}\"\n",
+						initialize_steps);
+		exit(1);
 	}
 }
 
@@ -4073,9 +4145,20 @@ runInitSteps(const char *initialize_steps)
 				op = "create tables";
 				initCreateTables(con);
 				break;
+			case '{':
+				executeStatement(con, "begin");
+				break;
 			case 'g':
-				op = "generate";
-				initGenerateData(con);
+				op = "client generate";
+				initGenerateDataClientSide(con);
+				break;
+			case 'G':
+				op = "server generate";
+				initGenerateDataServerSide(con);
+				break;
+			case '}':
+				op = "commit";
+				executeStatement(con, "commit");
 				break;
 			case 'v':
 				op = "vacuum";
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index c441626d7c..256b377e09 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -113,7 +113,7 @@ pgbench(
 
 # Again, with all possible options
 pgbench(
-	'--initialize --init-steps=dtpvg --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=regress_pgbench_tap_1_ts --index-tablespace=regress_pgbench_tap_1_ts --partitions=2 --partition-method=hash',
+	'--initialize --init-steps=dtpv{g} --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=regress_pgbench_tap_1_ts --index-tablespace=regress_pgbench_tap_1_ts --partitions=2 --partition-method=hash',
 	0,
 	[qr{^$}i],
 	[
@@ -130,7 +130,7 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
+	'--initialize --init-steps=dtpv{G}vv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
 	0,
 	[qr{^$}],
 	[
@@ -138,7 +138,7 @@ pgbench(
 		qr{creating tables},
 		qr{creating 3 partitions},
 		qr{creating primary keys},
-		qr{.* of .* tuples \(.*\) done},
+		qr{generating data server side},
 		qr{creating foreign keys},
 		qr{(?!vacuuming)}, # no vacuum
 		qr{done in \d+\.\d\d s }
diff --git a/src/bin/pgbench/t/002_pgbench_no_server.pl b/src/bin/pgbench/t/002_pgbench_no_server.pl
index 1e9542af3f..43b20ebcde 100644
--- a/src/bin/pgbench/t/002_pgbench_no_server.pl
+++ b/src/bin/pgbench/t/002_pgbench_no_server.pl
@@ -147,7 +147,27 @@ my @options = (
 	[
 		'invalid init step',
 		'-i -I dta',
-		[ qr{unrecognized initialization step}, qr{allowed steps are} ]
+		[ qr{unrecognized initialization step}, qr{Allowed step characters are} ]
+	],
+	[
+		'invalid init step begin/begin',
+		'-i -I {{',
+		[ qr{nested transactions are not supported} ]
+	],
+	[
+		'invalid init step end',
+		'-i -I }',
+		[ qr{does not have a matching BEGIN} ]
+	],
+	[
+		'invalid init step begin',
+		'-i -I {dt',
+		[ qr{does not have a matching COMMIT} ]
+	],
+	[
+		'invalid vacuum inside transaction block',
+		'-i -I {v}',
+		[ qr{VACUUM cannot run inside a transaction block} ]
 	],
 	[
 		'bad random seed',

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index e3a0abb4c7..d3d483a380 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -193,12 +193,15 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
           </listitem>
          </varlistentry>
          <varlistentry>
-          <term><literal>g</literal> (Generate data)</term>
+          <term><literal>g</literal> or <literal>G</literal> (Generate data, client or server side)</term>
           <listitem>
            <para>
             Generate data and load it into the standard tables,
             replacing any data already present.
            </para>
+           <para>
+            When data is generated server side, there is no progress output.
+           </para>
           </listitem>
          </varlistentry>
          <varlistentry>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 03bcd22996..e3c1e55bbb 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -131,8 +131,14 @@ static int	pthread_join(pthread_t th, void **thread_return);
 /********************************************************************
  * some configurable parameters */
 
+/*
+ * we do all data generation in one transaction to enable the backend's
+ * data-loading optimizations
+ */
 #define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
 
+#define ALL_INIT_STEPS "dtgGvpf"	/* all possible steps */
+
 #define LOG_STEP_SECONDS	5	/* seconds between log messages */
 #define DEFAULT_NXACTS	10		/* default nxacts */
 
@@ -627,7 +633,7 @@ usage(void)
 		   "  %s [OPTION]... [DBNAME]\n"
 		   "\nInitialization options:\n"
 		   "  -i, --initialize         invokes initialization mode\n"
-		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
+		   "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
 		   "                           run selected initialization steps\n"
 		   "  -F, --fillfactor=NUM     set fill factor\n"
 		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
@@ -3803,10 +3809,23 @@ append_fillfactor(char *opts, int len)
 }
 
 /*
- * Fill the standard tables with some data
+ * truncate away any old data, in one command in case there are foreign keys
  */
 static void
-initGenerateData(PGconn *con)
+initTruncateTables(PGconn *con)
+{
+	executeStatement(con, "truncate table "
+					 "pgbench_accounts, "
+					 "pgbench_branches, "
+					 "pgbench_history, "
+					 "pgbench_tellers");
+}
+
+/*
+ * Fill the standard tables with some data, from the client side
+ */
+static void
+initGenerateDataClientSide(PGconn *con)
 {
 	char		sql[256];
 	PGresult   *res;
@@ -3820,7 +3839,7 @@ initGenerateData(PGconn *con)
 				remaining_sec;
 	int			log_interval = 1;
 
-	fprintf(stderr, "generating data...\n");
+	fprintf(stderr, "generating data client side...\n");
 
 	/*
 	 * we do all of this in one transaction to enable the backend's
@@ -3828,15 +3847,7 @@ initGenerateData(PGconn *con)
 	 */
 	executeStatement(con, "begin");
 
-	/*
-	 * truncate away any old data, in one command in case there are foreign
-	 * keys
-	 */
-	executeStatement(con, "truncate table "
-					 "pgbench_accounts, "
-					 "pgbench_branches, "
-					 "pgbench_history, "
-					 "pgbench_tellers");
+	initTruncateTables(con);
 
 	/*
 	 * fill branches, tellers, accounts in that order in case foreign keys
@@ -3940,6 +3951,49 @@ initGenerateData(PGconn *con)
 	executeStatement(con, "commit");
 }
 
+/*
+ * Fill the standard tables with some data, from the server side
+ *
+ * As already the case with the client-side filling, the filler
+ * column defaults to NULL in pgbench_branches and pgbench_tellers,
+ * and is a blank-padded string in pgbench_accounts.
+ */
+static void
+initGenerateDataServerSide(PGconn *con)
+{
+	char		sql[256];
+
+	fprintf(stderr, "generating data server side...\n");
+
+	/*
+	 * we do all of this in one transaction to enable the backend's
+	 * data-loading optimizations
+	 */
+	executeStatement(con, "begin");
+
+	initTruncateTables(con);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_branches(bid,bbalance) "
+			 "select bid, 0 "
+			 "from generate_series(1, %d) as bid", scale);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_tellers(tid,bid,tbalance) "
+			 "select tid, (tid - 1) / %d + 1, 0 "
+			 "from generate_series(1, %d) as tid", ntellers, scale * ntellers);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_accounts(aid,bid,abalance,filler) "
+			 "select aid, (aid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, %d) as aid", naccounts, scale * naccounts);
+	executeStatement(con, sql);
+
+	executeStatement(con, "commit");
+}
+
 /*
  * Invoke vacuum on the standard tables
  */
@@ -4020,21 +4074,20 @@ initCreateFKeys(PGconn *con)
 static void
 checkInitSteps(const char *initialize_steps)
 {
-	const char *step;
-
 	if (initialize_steps[0] == '\0')
 	{
 		fprintf(stderr, "no initialization steps specified\n");
 		exit(1);
 	}
 
-	for (step = initialize_steps; *step != '\0'; step++)
+	for (const char *step = initialize_steps; *step != '\0'; step++)
 	{
-		if (strchr("dtgvpf ", *step) == NULL)
+		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
 		{
-			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
+			fprintf(stderr,
+					"unrecognized initialization step \"%c\"\n"
+					"Allowed step characters are: \"" ALL_INIT_STEPS "\".\n",
 					*step);
-			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
 			exit(1);
 		}
 	}
@@ -4075,8 +4128,12 @@ runInitSteps(const char *initialize_steps)
 				initCreateTables(con);
 				break;
 			case 'g':
-				op = "generate";
-				initGenerateData(con);
+				op = "client generate";
+				initGenerateDataClientSide(con);
+				break;
+			case 'G':
+				op = "server generate";
+				initGenerateDataServerSide(con);
 				break;
 			case 'v':
 				op = "vacuum";
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index c441626d7c..4384d0072a 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -130,7 +130,7 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
+	'--initialize --init-steps=dtpvGvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
 	0,
 	[qr{^$}],
 	[
@@ -138,7 +138,7 @@ pgbench(
 		qr{creating tables},
 		qr{creating 3 partitions},
 		qr{creating primary keys},
-		qr{.* of .* tuples \(.*\) done},
+		qr{generating data server side},
 		qr{creating foreign keys},
 		qr{(?!vacuuming)}, # no vacuum
 		qr{done in \d+\.\d\d s }
diff --git a/src/bin/pgbench/t/002_pgbench_no_server.pl b/src/bin/pgbench/t/002_pgbench_no_server.pl
index 1e9542af3f..8b6d442812 100644
--- a/src/bin/pgbench/t/002_pgbench_no_server.pl
+++ b/src/bin/pgbench/t/002_pgbench_no_server.pl
@@ -147,7 +147,7 @@ my @options = (
 	[
 		'invalid init step',
 		'-i -I dta',
-		[ qr{unrecognized initialization step}, qr{allowed steps are} ]
+		[ qr{unrecognized initialization step}, qr{Allowed step characters are} ]
 	],
 	[
 		'bad random seed',

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index e3a0abb4c7..7be9c81c43 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -193,12 +193,25 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
           </listitem>
          </varlistentry>
          <varlistentry>
-          <term><literal>g</literal> (Generate data)</term>
+          <term><literal>g</literal> or <literal>G</literal> (Generate data, client-side or server-side)</term>
           <listitem>
            <para>
             Generate data and load it into the standard tables,
             replacing any data already present.
            </para>
+           <para>
+            With <literal>g</literal> (client-side data generation),
+            data is generated in <command>pgbench</command> client and then
+            sent to the server. This uses the client/server bandwidth
+            extensively through a <command>COPY</command>.
+           </para>
+           <para>
+            With <literal>G</literal> (server-side data generation),
+            only limited queries are sent from <command>pgbench</command>
+            client and then data is actually generated in the server.
+            No significant bandwidth is required for this variant, but
+            the server will do more work.
+           </para>
           </listitem>
          </varlistentry>
          <varlistentry>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 03bcd22996..7f5c1d00c8 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -131,8 +131,14 @@ static int	pthread_join(pthread_t th, void **thread_return);
 /********************************************************************
  * some configurable parameters */
 
+/*
+ * we do all data generation in one transaction to enable the backend's
+ * data-loading optimizations
+ */
 #define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
 
+#define ALL_INIT_STEPS "dtgGvpf"	/* all possible steps */
+
 #define LOG_STEP_SECONDS	5	/* seconds between log messages */
 #define DEFAULT_NXACTS	10		/* default nxacts */
 
@@ -627,7 +633,7 @@ usage(void)
 		   "  %s [OPTION]... [DBNAME]\n"
 		   "\nInitialization options:\n"
 		   "  -i, --initialize         invokes initialization mode\n"
-		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
+		   "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
 		   "                           run selected initialization steps\n"
 		   "  -F, --fillfactor=NUM     set fill factor\n"
 		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
@@ -3803,10 +3809,23 @@ append_fillfactor(char *opts, int len)
 }
 
 /*
- * Fill the standard tables with some data
+ * truncate away any old data, in one command in case there are foreign keys
  */
 static void
-initGenerateData(PGconn *con)
+initTruncateTables(PGconn *con)
+{
+	executeStatement(con, "truncate table "
+					 "pgbench_accounts, "
+					 "pgbench_branches, "
+					 "pgbench_history, "
+					 "pgbench_tellers");
+}
+
+/*
+ * Fill the standard tables with some data, from the client side
+ */
+static void
+initGenerateDataClientSide(PGconn *con)
 {
 	char		sql[256];
 	PGresult   *res;
@@ -3820,7 +3839,7 @@ initGenerateData(PGconn *con)
 				remaining_sec;
 	int			log_interval = 1;
 
-	fprintf(stderr, "generating data...\n");
+	fprintf(stderr, "generating data client side...\n");
 
 	/*
 	 * we do all of this in one transaction to enable the backend's
@@ -3828,15 +3847,7 @@ initGenerateData(PGconn *con)
 	 */
 	executeStatement(con, "begin");
 
-	/*
-	 * truncate away any old data, in one command in case there are foreign
-	 * keys
-	 */
-	executeStatement(con, "truncate table "
-					 "pgbench_accounts, "
-					 "pgbench_branches, "
-					 "pgbench_history, "
-					 "pgbench_tellers");
+	initTruncateTables(con);
 
 	/*
 	 * fill branches, tellers, accounts in that order in case foreign keys
@@ -3940,6 +3951,49 @@ initGenerateData(PGconn *con)
 	executeStatement(con, "commit");
 }
 
+/*
+ * Fill the standard tables with some data, from the server side
+ *
+ * As already the case with the client-side filling, the filler
+ * column defaults to NULL in pgbench_branches and pgbench_tellers,
+ * and is a blank-padded string in pgbench_accounts.
+ */
+static void
+initGenerateDataServerSide(PGconn *con)
+{
+	char		sql[256];
+
+	fprintf(stderr, "generating data server side...\n");
+
+	/*
+	 * we do all of this in one transaction to enable the backend's
+	 * data-loading optimizations
+	 */
+	executeStatement(con, "begin");
+
+	initTruncateTables(con);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_branches(bid,bbalance) "
+			 "select bid, 0 "
+			 "from generate_series(1, %d) as bid", nbranches * scale);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_tellers(tid,bid,tbalance) "
+			 "select tid, (tid - 1) / %d + 1, 0 "
+			 "from generate_series(1, %d) as tid", ntellers, ntellers * scale);
+	executeStatement(con, sql);
+
+	snprintf(sql, sizeof(sql),
+			 "insert into pgbench_accounts(aid,bid,abalance,filler) "
+			 "select aid, (aid - 1) / %d + 1, 0, '' "
+			 "from generate_series(1, "INT64_FORMAT") as aid", naccounts, (int64) naccounts * scale);
+	executeStatement(con, sql);
+
+	executeStatement(con, "commit");
+}
+
 /*
  * Invoke vacuum on the standard tables
  */
@@ -4020,21 +4074,20 @@ initCreateFKeys(PGconn *con)
 static void
 checkInitSteps(const char *initialize_steps)
 {
-	const char *step;
-
 	if (initialize_steps[0] == '\0')
 	{
 		fprintf(stderr, "no initialization steps specified\n");
 		exit(1);
 	}
 
-	for (step = initialize_steps; *step != '\0'; step++)
+	for (const char *step = initialize_steps; *step != '\0'; step++)
 	{
-		if (strchr("dtgvpf ", *step) == NULL)
+		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
 		{
-			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
+			fprintf(stderr,
+					"unrecognized initialization step \"%c\"\n"
+					"Allowed step characters are: \"" ALL_INIT_STEPS "\".\n",
 					*step);
-			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
 			exit(1);
 		}
 	}
@@ -4075,8 +4128,12 @@ runInitSteps(const char *initialize_steps)
 				initCreateTables(con);
 				break;
 			case 'g':
-				op = "generate";
-				initGenerateData(con);
+				op = "client generate";
+				initGenerateDataClientSide(con);
+				break;
+			case 'G':
+				op = "server generate";
+				initGenerateDataServerSide(con);
 				break;
 			case 'v':
 				op = "vacuum";
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index c441626d7c..4384d0072a 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -130,7 +130,7 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
+	'--initialize --init-steps=dtpvGvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
 	0,
 	[qr{^$}],
 	[
@@ -138,7 +138,7 @@ pgbench(
 		qr{creating tables},
 		qr{creating 3 partitions},
 		qr{creating primary keys},
-		qr{.* of .* tuples \(.*\) done},
+		qr{generating data server side},
 		qr{creating foreign keys},
 		qr{(?!vacuuming)}, # no vacuum
 		qr{done in \d+\.\d\d s }
diff --git a/src/bin/pgbench/t/002_pgbench_no_server.pl b/src/bin/pgbench/t/002_pgbench_no_server.pl
index 1e9542af3f..8b6d442812 100644
--- a/src/bin/pgbench/t/002_pgbench_no_server.pl
+++ b/src/bin/pgbench/t/002_pgbench_no_server.pl
@@ -147,7 +147,7 @@ my @options = (
 	[
 		'invalid init step',
 		'-i -I dta',
-		[ qr{unrecognized initialization step}, qr{allowed steps are} ]
+		[ qr{unrecognized initialization step}, qr{Allowed step characters are} ]
 	],
 	[
 		'bad random seed',

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index e3a0abb4c7..a6370f00dd 100644
*** a/doc/src/sgml/ref/pgbench.sgml
--- b/doc/src/sgml/ref/pgbench.sgml
***************
*** 193,204 **** pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
            </listitem>
           </varlistentry>
           <varlistentry>
!           <term><literal>g</literal> (Generate data)</term>
            <listitem>
             <para>
              Generate data and load it into the standard tables,
              replacing any data already present.
             </para>
            </listitem>
           </varlistentry>
           <varlistentry>
--- 193,226 ----
            </listitem>
           </varlistentry>
           <varlistentry>
!           <term><literal>g</literal> or <literal>G</literal> (Generate data, client-side or server-side)</term>
            <listitem>
             <para>
              Generate data and load it into the standard tables,
              replacing any data already present.
             </para>
+            <para>
+             With <literal>g</literal> (client-side data generation),
+             data is generated in <command>pgbench</command> client and then
+             sent to the server. This uses the client/server bandwidth
+             extensively through a <command>COPY</command>.
+             Using <literal>g</literal> causes logging to print one message
+             each 100,000 rows when generating data into
+             <structname>pgbench_accounts</structname> table.
+            </para>
+            <para>
+             With <literal>G</literal> (server-side data generation),
+             only limited queries are sent from <command>pgbench</command>
+             client and then data is actually generated in the server.
+             No significant bandwidth is required for this variant, but
+             the server will do more work.
+             Using <literal>G</literal> causes logging to print no progress
+             message when generating data into
+             <structname>pgbench_accounts</structname> table.
+            </para>
+            <para>
+             
+            </para>
            </listitem>
           </varlistentry>
           <varlistentry>
***************
*** 262,270 **** pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
        <listitem>
         <para>
          Switch logging to quiet mode, producing only one progress message per 5
!         seconds. The default logging prints one message each 100000 rows, which
          often outputs many lines per second (especially on good hardware).
         </para>
        </listitem>
       </varlistentry>
  
--- 284,296 ----
        <listitem>
         <para>
          Switch logging to quiet mode, producing only one progress message per 5
!         seconds. The default logging prints one message each 100,000 rows, which
          often outputs many lines per second (especially on good hardware).
         </para>
+        <para>
+         This setting has no effect if <literal>G</literal> is specified
+         in <option>-I</option>.
+        </para>
        </listitem>
       </varlistentry>
  
diff --git a/src/bin/pgbench/pgbenchindex 03bcd22996..14dbc4510c 100644
*** a/src/bin/pgbench/pgbench.c
--- b/src/bin/pgbench/pgbench.c
***************
*** 132,137 **** static int	pthread_join(pthread_t th, void **thread_return);
--- 132,138 ----
   * some configurable parameters */
  
  #define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
+ #define ALL_INIT_STEPS "dtgGvpf"	/* all possible steps */
  
  #define LOG_STEP_SECONDS	5	/* seconds between log messages */
  #define DEFAULT_NXACTS	10		/* default nxacts */
***************
*** 627,633 **** usage(void)
  		   "  %s [OPTION]... [DBNAME]\n"
  		   "\nInitialization options:\n"
  		   "  -i, --initialize         invokes initialization mode\n"
! 		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
  		   "                           run selected initialization steps\n"
  		   "  -F, --fillfactor=NUM     set fill factor\n"
  		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
--- 628,634 ----
  		   "  %s [OPTION]... [DBNAME]\n"
  		   "\nInitialization options:\n"
  		   "  -i, --initialize         invokes initialization mode\n"
! 		   "  -I, --init-steps=[" ALL_INIT_STEPS "]+ (default \"" DEFAULT_INIT_STEPS "\")\n"
  		   "                           run selected initialization steps\n"
  		   "  -F, --fillfactor=NUM     set fill factor\n"
  		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
***************
*** 3803,3812 **** append_fillfactor(char *opts, int len)
  }
  
  /*
!  * Fill the standard tables with some data
   */
  static void
! initGenerateData(PGconn *con)
  {
  	char		sql[256];
  	PGresult   *res;
--- 3804,3826 ----
  }
  
  /*
!  * Truncate away any old data, in one command in case there are foreign keys
   */
  static void
! initTruncateTables(PGconn *con)
! {
! 	executeStatement(con, "truncate table "
! 					 "pgbench_accounts, "
! 					 "pgbench_branches, "
! 					 "pgbench_history, "
! 					 "pgbench_tellers");
! }
! 
! /*
!  * Fill the standard tables with some data generated and sent from the client
!  */
! static void
! initGenerateDataClientSide(PGconn *con)
  {
  	char		sql[256];
  	PGresult   *res;
***************
*** 3820,3826 **** initGenerateData(PGconn *con)
  				remaining_sec;
  	int			log_interval = 1;
  
! 	fprintf(stderr, "generating data...\n");
  
  	/*
  	 * we do all of this in one transaction to enable the backend's
--- 3834,3840 ----
  				remaining_sec;
  	int			log_interval = 1;
  
! 	fprintf(stderr, "generating data (client-side)...\n");
  
  	/*
  	 * we do all of this in one transaction to enable the backend's
***************
*** 3828,3842 **** initGenerateData(PGconn *con)
  	 */
  	executeStatement(con, "begin");
  
! 	/*
! 	 * truncate away any old data, in one command in case there are foreign
! 	 * keys
! 	 */
! 	executeStatement(con, "truncate table "
! 					 "pgbench_accounts, "
! 					 "pgbench_branches, "
! 					 "pgbench_history, "
! 					 "pgbench_tellers");
  
  	/*
  	 * fill branches, tellers, accounts in that order in case foreign keys
--- 3842,3849 ----
  	 */
  	executeStatement(con, "begin");
  
! 	/* truncate away any old data */
! 	initTruncateTables(con);
  
  	/*
  	 * fill branches, tellers, accounts in that order in case foreign keys
***************
*** 3940,3945 **** initGenerateData(PGconn *con)
--- 3947,3997 ----
  	executeStatement(con, "commit");
  }
  
+ /*
+  * Fill the standard tables with some data generated on the server
+  *
+  * As already the case with the client-side data generation, the filler
+  * column defaults to NULL in pgbench_branches and pgbench_tellers,
+  * and is a blank-padded string in pgbench_accounts.
+  */
+ static void
+ initGenerateDataServerSide(PGconn *con)
+ {
+ 	char		sql[256];
+ 
+ 	fprintf(stderr, "generating data (server-side)...\n");
+ 
+ 	/*
+ 	 * we do all of this in one transaction to enable the backend's
+ 	 * data-loading optimizations
+ 	 */
+ 	executeStatement(con, "begin");
+ 
+ 	/* truncate away any old data */
+ 	initTruncateTables(con);
+ 
+ 	snprintf(sql, sizeof(sql),
+ 			 "insert into pgbench_branches(bid,bbalance) "
+ 			 "select bid, 0 "
+ 			 "from generate_series(1, %d) as bid", nbranches * scale);
+ 	executeStatement(con, sql);
+ 
+ 	snprintf(sql, sizeof(sql),
+ 			 "insert into pgbench_tellers(tid,bid,tbalance) "
+ 			 "select tid, (tid - 1) / %d + 1, 0 "
+ 			 "from generate_series(1, %d) as tid", ntellers, ntellers * scale);
+ 	executeStatement(con, sql);
+ 
+ 	snprintf(sql, sizeof(sql),
+ 			 "insert into pgbench_accounts(aid,bid,abalance,filler) "
+ 			 "select aid, (aid - 1) / %d + 1, 0, '' "
+ 			 "from generate_series(1, "INT64_FORMAT") as aid",
+ 			 naccounts, (int64) naccounts * scale);
+ 	executeStatement(con, sql);
+ 
+ 	executeStatement(con, "commit");
+ }
+ 
  /*
   * Invoke vacuum on the standard tables
   */
***************
*** 4020,4040 **** initCreateFKeys(PGconn *con)
  static void
  checkInitSteps(const char *initialize_steps)
  {
- 	const char *step;
- 
  	if (initialize_steps[0] == '\0')
  	{
  		fprintf(stderr, "no initialization steps specified\n");
  		exit(1);
  	}
  
! 	for (step = initialize_steps; *step != '\0'; step++)
  	{
! 		if (strchr("dtgvpf ", *step) == NULL)
  		{
! 			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
  					*step);
! 			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
  			exit(1);
  		}
  	}
--- 4072,4092 ----
  static void
  checkInitSteps(const char *initialize_steps)
  {
  	if (initialize_steps[0] == '\0')
  	{
  		fprintf(stderr, "no initialization steps specified\n");
  		exit(1);
  	}
  
! 	for (const char *step = initialize_steps; *step != '\0'; step++)
  	{
! 		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
  		{
! 			fprintf(stderr,
! 					"unrecognized initialization step \"%c\"\n",
  					*step);
! 			fprintf(stderr,
! 					"Allowed step characters are: \"" ALL_INIT_STEPS "\".\n");
  			exit(1);
  		}
  	}
***************
*** 4075,4082 **** runInitSteps(const char *initialize_steps)
  				initCreateTables(con);
  				break;
  			case 'g':
! 				op = "generate";
! 				initGenerateData(con);
  				break;
  			case 'v':
  				op = "vacuum";
--- 4127,4138 ----
  				initCreateTables(con);
  				break;
  			case 'g':
! 				op = "client-side generate";
! 				initGenerateDataClientSide(con);
! 				break;
! 			case 'G':
! 				op = "server-side generate";
! 				initGenerateDataServerSide(con);
  				break;
  			case 'v':
  				op = "vacuum";
diff --git a/src/bin/pgbench/t/0index c441626d7c..1845869016 100644
*** a/src/bin/pgbench/t/001_pgbench_with_server.pl
--- b/src/bin/pgbench/t/001_pgbench_with_server.pl
***************
*** 130,136 **** pgbench(
  
  # Test interaction of --init-steps with legacy step-selection options
  pgbench(
! 	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
  	0,
  	[qr{^$}],
  	[
--- 130,136 ----
  
  # Test interaction of --init-steps with legacy step-selection options
  pgbench(
! 	'--initialize --init-steps=dtpvGvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
  	0,
  	[qr{^$}],
  	[
***************
*** 138,144 **** pgbench(
  		qr{creating tables},
  		qr{creating 3 partitions},
  		qr{creating primary keys},
! 		qr{.* of .* tuples \(.*\) done},
  		qr{creating foreign keys},
  		qr{(?!vacuuming)}, # no vacuum
  		qr{done in \d+\.\d\d s }
--- 138,144 ----
  		qr{creating tables},
  		qr{creating 3 partitions},
  		qr{creating primary keys},
! 		qr{generating data \(server-side\)},
  		qr{creating foreign keys},
  		qr{(?!vacuuming)}, # no vacuum
  		qr{done in \d+\.\d\d s }
diff --git a/src/bin/pgbench/t/002_pgbench_no_serveindex 1e9542af3f..8b6d442812 100644
*** a/src/bin/pgbench/t/002_pgbench_no_server.pl
--- b/src/bin/pgbench/t/002_pgbench_no_server.pl
***************
*** 147,153 **** my @options = (
  	[
  		'invalid init step',
  		'-i -I dta',
! 		[ qr{unrecognized initialization step}, qr{allowed steps are} ]
  	],
  	[
  		'bad random seed',
--- 147,153 ----
  	[
  		'invalid init step',
  		'-i -I dta',
! 		[ qr{unrecognized initialization step}, qr{Allowed step characters are} ]
  	],
  	[
  		'bad random seed',

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 14dbc4510c..95b23895ff 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -4080,7 +4080,7 @@ checkInitSteps(const char *initialize_steps)
 
 	for (const char *step = initialize_steps; *step != '\0'; step++)
 	{
-		if (strchr(ALL_INIT_STEPS " ", *step) == NULL)
+		if (strchr(ALL_INIT_STEPS, *step) == NULL)
 		{
 			fprintf(stderr,
 					"unrecognized initialization step \"%c\"\n",

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 4c48a58ed2..5008377998 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -168,7 +168,8 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
         initialization steps to be performed, using one character per step.
         Each step is invoked in the specified order.
         The default is <literal>dtgvp</literal>.
-        The available steps are:
+        The space character is accepted as a no-op, and the other available
+        steps are:
 
         <variablelist>
          <varlistentry>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 14dbc4510c..4178127c21 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -4104,6 +4104,9 @@ runInitSteps(const char *initialize_steps)
 	double		run_time = 0.0;
 	bool		first = true;
 
+	/* check that all steps are valid before executing them */
+	checkInitSteps(initialize_steps);
+
 	initPQExpBuffer(&stats);
 
 	if ((con = doConnect()) == NULL)
@@ -5501,7 +5504,6 @@ main(int argc, char **argv)
 				if (initialize_steps)
 					pg_free(initialize_steps);
 				initialize_steps = pg_strdup(optarg);
-				checkInitSteps(initialize_steps);
 				initialization_option_set = true;
 				break;
 			case 'h':
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index 1845869016..4e3d3e464c 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -130,7 +130,7 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvGvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
+	'--initialize --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
 	0,
 	[qr{^$}],
 	[
@@ -143,7 +143,9 @@ pgbench(
 		qr{(?!vacuuming)}, # no vacuum
 		qr{done in \d+\.\d\d s }
 	],
-	'pgbench --init-steps');
+	'pgbench --init-steps',
+	undef,
+	'--init-steps= dtpvGvv');
 
 # Run all builtin scripts, for a few transactions each
 pgbench(