pg_stat_wal_write statistics view

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 5b67def..ef6bc1c 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -357,6 +357,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       wal writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -1833,6 +1841,70 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of wal writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of wal writes that are carried out by background workers such as checkpointer, 
+      writer and walwriter. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of wal pages written to the disk</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of wal write processing where files 
+      are written to disk, in milliseconds.
+      This field data will be populated only when the track_io_timing GUC is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of wal write processing where files 
+      are synchronized to disk, in milliseconds.
+      This field data will be populated only when the track_io_timing GUC is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the wal writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -2612,6 +2684,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index f23e108..2219433 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -2333,6 +2333,8 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2450,6 +2452,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2470,6 +2477,33 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				LocalWalWritesStats.m_wal_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				LocalWalWritesStats.m_wal_total_write_time = 0;
+			}
+
+			/* check whether writer is a background process or not? */
+			if (AmBackgroundWriterProcess() ||
+				AmWalWriterProcess() ||
+				AmCheckpointerProcess())
+			{
+				LocalWalWritesStats.m_writes++;
+			}
+			else
+			{
+				LocalWalWritesStats.m_backend_writes++;
+			}
+
+			LocalWalWritesStats.m_write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2489,8 +2523,25 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					LocalWalWritesStats.m_wal_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+				{
+					LocalWalWritesStats.m_wal_total_sync_time = 0;
+				}
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2558,7 +2609,24 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				LocalWalWritesStats.m_wal_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				LocalWalWritesStats.m_wal_total_sync_time = 0;
+			}
 		}
 
 		/* signal that we need to wakeup walsenders later */
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 38be9cf..27223e2 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -854,6 +854,16 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites as 
+	SELECT
+	pg_stat_get_wal_backend_writes() AS backend_writes,
+        pg_stat_get_wal_writes() AS writes,
+        pg_stat_get_wal_write_blocks() AS write_blocks,
+        pg_stat_get_wal_write_time() AS write_time,
+        pg_stat_get_wal_sync_time() AS sync_time,
+	pg_stat_get_wal_stat_reset_time() AS stats_reset;
+
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index dcb4cf2..1cd623d 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -284,6 +284,7 @@ BackgroundWriterMain(void)
 		 * Send off activity statistics to the stats collector
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		if (FirstCallSinceLastCheckpoint())
 		{
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index fe9041f..8549f8f 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -538,6 +538,7 @@ CheckpointerMain(void)
 		 * stats message types.)
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		/*
 		 * Sleep until we are signaled or it's time for another checkpoint or
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 7176cf1..fe88411 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -126,6 +126,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -222,6 +231,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -301,6 +311,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -834,6 +845,9 @@ pgstat_report_stat(bool force)
 
 	/* Now, send function statistics */
 	pgstat_send_funcstats();
+
+	/* Now, send wal writes statistics */
+	pgstat_send_walwrites();
 }
 
 /*
@@ -1260,11 +1274,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2478,6 +2494,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -3687,6 +3718,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -3903,6 +3967,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) &msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4169,6 +4237,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+ 	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4425,6 +4499,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4432,6 +4507,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4484,6 +4560,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -4772,6 +4858,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -4826,6 +4913,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5388,6 +5487,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -5568,6 +5673,22 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.backend_writes += msg->m_backend_writes;
+	walwritesStats.writes += msg->m_writes;
+	walwritesStats.write_blocks += msg->m_write_blocks;
+	walwritesStats.total_write_time += msg->m_wal_total_write_time;
+	walwritesStats.total_sync_time += msg->m_wal_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index a575d8f..cf0c279 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index a987d0d..b8dcfc8 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1521,6 +1521,44 @@ pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
 }
 
 Datum
+pg_stat_get_wal_backend_writes(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_INT64(pgstat_fetch_stat_walwrites()->backend_writes);
+}
+
+Datum
+pg_stat_get_wal_writes(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_INT64(pgstat_fetch_stat_walwrites()->writes);
+}
+
+Datum
+pg_stat_get_wal_write_blocks(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_INT64(pgstat_fetch_stat_walwrites()->write_blocks);
+}
+
+Datum
+pg_stat_get_wal_write_time(PG_FUNCTION_ARGS)
+{
+	/* time is already in msec, just convert to double for presentation */
+	PG_RETURN_FLOAT8((double) pgstat_fetch_stat_walwrites()->total_write_time);
+}
+
+Datum
+pg_stat_get_wal_sync_time(PG_FUNCTION_ARGS)
+{
+	/* time is already in msec, just convert to double for presentation */
+	PG_RETURN_FLOAT8((double) pgstat_fetch_stat_walwrites()->total_sync_time);
+}
+
+Datum
+pg_stat_get_wal_stat_reset_time(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_TIMESTAMPTZ(pgstat_fetch_stat_walwrites()->stat_reset_timestamp);
+}
+
+Datum
 pg_stat_get_xact_numscans(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 41c12af..722ad53 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2871,6 +2871,18 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3354 ( pg_stat_get_wal_backend_writes PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_backend_writes _null_ _null_ _null_ ));
+DESCR("statistics: number of backend wal writes statistics");
+DATA(insert OID = 3355 ( pg_stat_get_wal_writes PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_writes _null_ _null_ _null_ ));
+DESCR("statistics: number of background process wal writes statistics");
+DATA(insert OID = 3356 ( pg_stat_get_wal_write_blocks PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_write_blocks _null_ _null_ _null_ ));
+DESCR("statistics: number of wal blocks written statistics");
+DATA(insert OID = 3357 ( pg_stat_get_wal_write_time PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 701 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_write_time _null_ _null_ _null_ ));
+DESCR("statistics: get total time spent in writing wal blocks to disk, in milliseconds");
+DATA(insert OID = 3358 ( pg_stat_get_wal_sync_time PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 701 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_sync_time _null_ _null_ _null_ ));
+DESCR("statistics: get total time spent in synchronizing buffers to disk, in milliseconds");
+DATA(insert OID = 3359 ( pg_stat_get_wal_stat_reset_time PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 1184 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_stat_reset_time _null_ _null_ _null_ ));
+DESCR("statistics: last reset for the wal writes statistics");
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index de8225b..1c62e5a 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -423,6 +425,22 @@ typedef struct PgStat_MsgBgWriter
 } PgStat_MsgBgWriter;
 
 /* ----------
+ * PgStat_MsgWalWrites			Sent by the backend or walwriter or writer
+ *								or checkpointer process
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+
+	PgStat_Counter m_backend_writes;	/* No of writes by backend */
+	PgStat_Counter m_writes;	/* No of writes by background processes */
+	PgStat_Counter m_write_blocks;		/* Total no of pages written */
+	PgStat_Counter m_wal_total_write_time;		/* times in milliseconds */
+	PgStat_Counter m_wal_total_sync_time;		/* times in milliseconds */
+}	PgStat_MsgWalWrites;
+
+/* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
  */
@@ -555,6 +573,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +713,18 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter writes;		/* No of writes by background processes */
+	PgStat_Counter write_blocks;	/* Total no of pages written */
+	PgStat_Counter total_write_time;	/* Total write time */
+	PgStat_Counter total_sync_time;		/* Total sync time */
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+}	PgStat_WalWritesStats;
 
 /* ----------
  * Backend states
@@ -1008,6 +1039,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1200,6 +1236,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1214,5 +1251,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif   /* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index c661f1d..402a396 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1945,6 +1945,12 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT pg_stat_get_wal_backend_writes() AS backend_writes,
+    pg_stat_get_wal_writes() AS writes,
+    pg_stat_get_wal_write_blocks() AS write_blocks,
+    pg_stat_get_wal_write_time() AS write_time,
+    pg_stat_get_wal_sync_time() AS sync_time,
+    pg_stat_get_wal_stat_reset_time() AS stats_reset;
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index d48abd7..b852069 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index b6daf96..00b2520 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5707,7 +5707,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         platforms.  You can use the <xref linkend="pgtesttiming"> tool to
         measure the overhead of timing on your system.
         I/O timing information is
-        displayed in <xref linkend="pg-stat-database-view">, in the output of
+        displayed in <xref linkend="pg-stat-database-view">, 
+        <xref linkend="pg-stat-walwrites-view">, in the output of
         <xref linkend="sql-explain"> when the <literal>BUFFERS</> option is
         used, and by <xref linkend="pgstatstatements">.  Only superusers can
         change this setting.
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 9eaf43a..cb8b688 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -357,6 +357,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -1845,6 +1853,70 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes such as checkpointer, 
+      writer and walwriter. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -2624,6 +2696,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 64335f9..b635402 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -2335,6 +2335,8 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2452,6 +2454,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2472,6 +2479,29 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				LocalWalWritesStats.m_wal_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+				LocalWalWritesStats.m_wal_total_write_time = 0;
+
+			/* check whether writer is a background process or not? */
+			if (AmBackgroundWriterProcess() ||
+				AmWalWriterProcess() ||
+				AmCheckpointerProcess())
+			{
+				LocalWalWritesStats.m_writes++;
+			}
+			else
+				LocalWalWritesStats.m_backend_writes++;
+
+			LocalWalWritesStats.m_write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2491,8 +2521,23 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					LocalWalWritesStats.m_wal_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+					LocalWalWritesStats.m_wal_total_sync_time = 0;
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2560,7 +2605,22 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				LocalWalWritesStats.m_wal_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+				LocalWalWritesStats.m_wal_total_sync_time = 0;
 		}
 
 		/* signal that we need to wakeup walsenders later */
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 0bce209..c527fbc 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -854,6 +854,16 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites as
+	SELECT
+	pg_stat_get_wal_backend_writes() AS backend_writes,
+        pg_stat_get_wal_writes() AS writes,
+        pg_stat_get_wal_write_blocks() AS write_blocks,
+        pg_stat_get_wal_write_time() AS write_time,
+        pg_stat_get_wal_sync_time() AS sync_time,
+	pg_stat_get_wal_stat_reset_time() AS stats_reset;
+
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index dcb4cf2..1cd623d 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -284,6 +284,7 @@ BackgroundWriterMain(void)
 		 * Send off activity statistics to the stats collector
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		if (FirstCallSinceLastCheckpoint())
 		{
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index fe9041f..8549f8f 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -538,6 +538,7 @@ CheckpointerMain(void)
 		 * stats message types.)
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		/*
 		 * Sleep until we are signaled or it's time for another checkpoint or
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 7cacb1e..95a4d9b 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -126,6 +126,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -222,6 +231,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -301,6 +311,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -834,6 +845,9 @@ pgstat_report_stat(bool force)
 
 	/* Now, send function statistics */
 	pgstat_send_funcstats();
+
+	/* Now, send wal writes statistics */
+	pgstat_send_walwrites();
 }
 
 /*
@@ -1260,11 +1274,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2478,6 +2494,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -3693,6 +3724,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -3909,6 +3973,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) &msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4175,6 +4243,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4431,6 +4505,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4438,6 +4513,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4490,6 +4566,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -4778,6 +4864,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -4832,6 +4919,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5394,6 +5493,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -5574,6 +5679,22 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.backend_writes += msg->m_backend_writes;
+	walwritesStats.writes += msg->m_writes;
+	walwritesStats.write_blocks += msg->m_write_blocks;
+	walwritesStats.total_write_time += msg->m_wal_total_write_time;
+	walwritesStats.total_sync_time += msg->m_wal_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index a575d8f..cf0c279 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index a987d0d..b8dcfc8 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1521,6 +1521,44 @@ pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
 }
 
 Datum
+pg_stat_get_wal_backend_writes(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_INT64(pgstat_fetch_stat_walwrites()->backend_writes);
+}
+
+Datum
+pg_stat_get_wal_writes(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_INT64(pgstat_fetch_stat_walwrites()->writes);
+}
+
+Datum
+pg_stat_get_wal_write_blocks(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_INT64(pgstat_fetch_stat_walwrites()->write_blocks);
+}
+
+Datum
+pg_stat_get_wal_write_time(PG_FUNCTION_ARGS)
+{
+	/* time is already in msec, just convert to double for presentation */
+	PG_RETURN_FLOAT8((double) pgstat_fetch_stat_walwrites()->total_write_time);
+}
+
+Datum
+pg_stat_get_wal_sync_time(PG_FUNCTION_ARGS)
+{
+	/* time is already in msec, just convert to double for presentation */
+	PG_RETURN_FLOAT8((double) pgstat_fetch_stat_walwrites()->total_sync_time);
+}
+
+Datum
+pg_stat_get_wal_stat_reset_time(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_TIMESTAMPTZ(pgstat_fetch_stat_walwrites()->stat_reset_timestamp);
+}
+
+Datum
 pg_stat_get_xact_numscans(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 3d5d866..216c51d 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2900,6 +2900,18 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3354 ( pg_stat_get_wal_backend_writes PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_backend_writes _null_ _null_ _null_ ));
+DESCR("statistics: number of backend wal writes statistics");
+DATA(insert OID = 3355 ( pg_stat_get_wal_writes PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_writes _null_ _null_ _null_ ));
+DESCR("statistics: number of background process wal writes statistics");
+DATA(insert OID = 3356 ( pg_stat_get_wal_write_blocks PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_write_blocks _null_ _null_ _null_ ));
+DESCR("statistics: number of wal blocks written statistics");
+DATA(insert OID = 3357 ( pg_stat_get_wal_write_time PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 701 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_write_time _null_ _null_ _null_ ));
+DESCR("statistics: get total time spent in writing wal blocks to disk, in milliseconds");
+DATA(insert OID = 3358 ( pg_stat_get_wal_sync_time PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 701 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_sync_time _null_ _null_ _null_ ));
+DESCR("statistics: get total time spent in synchronizing buffers to disk, in milliseconds");
+DATA(insert OID = 3359 ( pg_stat_get_wal_stat_reset_time PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 1184 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_wal_stat_reset_time _null_ _null_ _null_ ));
+DESCR("statistics: last reset for the wal writes statistics");
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 60c78d1..c11055a 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -423,6 +425,22 @@ typedef struct PgStat_MsgBgWriter
 } PgStat_MsgBgWriter;
 
 /* ----------
+ * PgStat_MsgWalWrites			Sent by the backend or walwriter or writer
+ *								or checkpointer process
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+
+	PgStat_Counter m_backend_writes;	/* No of writes by backend */
+	PgStat_Counter m_writes;	/* No of writes by background processes */
+	PgStat_Counter m_write_blocks;		/* Total no of pages written */
+	PgStat_Counter m_wal_total_write_time;		/* times in milliseconds */
+	PgStat_Counter m_wal_total_sync_time;		/* times in milliseconds */
+}	PgStat_MsgWalWrites;
+
+/* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
  */
@@ -555,6 +573,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +713,18 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter writes;		/* No of writes by background processes */
+	PgStat_Counter write_blocks;	/* Total no of pages written */
+	PgStat_Counter total_write_time;	/* Total write time */
+	PgStat_Counter total_sync_time;		/* Total sync time */
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+}	PgStat_WalWritesStats;
 
 /* ----------
  * Backend states
@@ -1010,6 +1041,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1202,6 +1238,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1216,5 +1253,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif   /* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index bd13ae6..7f23d9a 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1945,6 +1945,12 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT pg_stat_get_wal_backend_writes() AS backend_writes,
+    pg_stat_get_wal_writes() AS writes,
+    pg_stat_get_wal_write_blocks() AS write_blocks,
+    pg_stat_get_wal_write_time() AS write_time,
+    pg_stat_get_wal_sync_time() AS sync_time,
+    pg_stat_get_wal_stat_reset_time() AS stats_reset;
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783..8448cac 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index ac339fb..ed833e0 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5732,7 +5732,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         platforms.  You can use the <xref linkend="pgtesttiming"> tool to
         measure the overhead of timing on your system.
         I/O timing information is
-        displayed in <xref linkend="pg-stat-database-view">, in the output of
+        displayed in <xref linkend="pg-stat-database-view">, 
+        <xref linkend="pg-stat-walwrites-view">, in the output of
         <xref linkend="sql-explain"> when the <literal>BUFFERS</> option is
         used, and by <xref linkend="pgstatstatements">.  Only superusers can
         change this setting.
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 9856968..b5ed688 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -357,6 +357,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -2207,6 +2215,108 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+     <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -2986,6 +3096,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 61ca81d..05a6903 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -860,6 +860,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2109,6 +2110,10 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (am_background_process())
+						LocalWalWritesStats.m_dirty_writes++;
+					else
+						LocalWalWritesStats.m_backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2319,6 +2324,34 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 }
 
 /*
+ * Check whether the current process is a normal backend or not.
+ * This function checks for the background processes that does
+ * some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns FALSE - when the current process is a normal backend
+ *		   TRUE - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (AmBackgroundWriterProcess() ||
+		AmWalWriterProcess() ||
+		AmCheckpointerProcess() ||
+		AmStartupProcess() ||
+		IsBackgroundWorker ||
+		am_walsender ||
+		am_autovacuum_worker)
+	{
+		return true;
+	}
+
+	return false;
+}
+
+/*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
  * If flexible == TRUE, we don't have to write as far as WriteRqst, but
@@ -2341,6 +2374,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2458,6 +2494,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2480,6 +2521,34 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					LocalWalWritesStats.m_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					LocalWalWritesStats.m_backend_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				LocalWalWritesStats.m_total_write_time = 0;
+				LocalWalWritesStats.m_backend_total_write_time = 0;
+			}
+
+			/* check whether writer is a normal backend or not? */
+			if (is_background_process)
+				LocalWalWritesStats.m_writes++;
+			else
+				LocalWalWritesStats.m_backend_writes++;
+
+			if (is_background_process)
+				LocalWalWritesStats.m_write_blocks += npages;
+			else
+				LocalWalWritesStats.m_backend_write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2499,8 +2568,29 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					if (is_background_process)
+						LocalWalWritesStats.m_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+					else
+						LocalWalWritesStats.m_backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+				{
+					LocalWalWritesStats.m_total_sync_time = 0;
+					LocalWalWritesStats.m_backend_total_sync_time = 0;
+				}
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2568,7 +2658,28 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					LocalWalWritesStats.m_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					LocalWalWritesStats.m_backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				LocalWalWritesStats.m_total_sync_time = 0;
+				LocalWalWritesStats.m_backend_total_sync_time = 0;
+			}
 		}
 
 		/* signal that we need to wakeup walsenders later */
@@ -7642,6 +7753,9 @@ StartupXLOG(void)
 		}
 	}
 
+	/* Report WAL write activity now */
+	pgstat_send_walwrites()
+
 	/*
 	 * Preallocate additional log files, if wanted.
 	 */
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index d357c8b..f424c9d 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -891,6 +891,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index 5b43a66..0f3b007 100644
--- a/src/backend/commands/vacuumlazy.c
+++ b/src/backend/commands/vacuumlazy.c
@@ -344,6 +344,8 @@ lazy_vacuum_rel(Relation onerel, int options, VacuumParams *params,
 						 onerel->rd_rel->relisshared,
 						 new_live_tuples,
 						 vacrelstats->new_dead_tuples);
+	/* In case if there is any WAL write activity, send it. */
+	pgstat_send_walwrites();
 	pgstat_progress_end_command();
 
 	/* and log the action if appropriate */
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 33ca749..5a42c69 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -132,7 +132,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index dcb4cf2..1cd623d 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -284,6 +284,7 @@ BackgroundWriterMain(void)
 		 * Send off activity statistics to the stats collector
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		if (FirstCallSinceLastCheckpoint())
 		{
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index fe9041f..8549f8f 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -538,6 +538,7 @@ CheckpointerMain(void)
 		 * stats message types.)
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		/*
 		 * Sleep until we are signaled or it's time for another checkpoint or
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 56a8bf2..5400757 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -139,6 +139,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -253,6 +262,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -333,6 +343,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -874,6 +885,9 @@ pgstat_report_stat(bool force)
 
 	/* Now, send function statistics */
 	pgstat_send_funcstats();
+
+	/* Now, send wal writes statistics */
+	pgstat_send_walwrites();
 }
 
 /*
@@ -1300,11 +1314,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2543,6 +2559,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4123,6 +4154,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4339,6 +4403,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4605,6 +4673,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4861,6 +4935,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4868,6 +4943,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4920,6 +4996,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -5208,6 +5294,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5262,6 +5349,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5824,6 +5923,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6004,6 +6109,27 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.writes += msg->m_writes;
+	walwritesStats.backend_writes += msg->m_backend_writes;
+	walwritesStats.dirty_writes += msg->m_dirty_writes;
+	walwritesStats.backend_dirty_writes += msg->m_backend_dirty_writes;
+	walwritesStats.write_blocks += msg->m_write_blocks;
+	walwritesStats.backend_write_blocks += msg->m_backend_write_blocks;
+	walwritesStats.total_write_time += msg->m_total_write_time;
+	walwritesStats.backend_total_write_time += msg->m_backend_total_write_time;
+	walwritesStats.total_sync_time += msg->m_total_sync_time;
+	walwritesStats.backend_total_sync_time += msg->m_backend_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index a575d8f..cf0c279 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index cfc3fba..677473e 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -2106,6 +2106,9 @@ WalSndLoop(WalSndSendDataCallback send_data)
 		/* Send keepalive if the time has come */
 		WalSndKeepaliveIfNecessary(now);
 
+		/* in case if it has any WAL write activity, send now */
+		pgstat_send_walwrites();
+
 		/*
 		 * We don't block if not caught up, unless there is unsent data
 		 * pending in which case we'd better block until the socket is
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index dd2b924..f2d8d50 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1859,3 +1859,42 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 								   heap_form_tuple(tupdesc, values, nulls)));
 }
+
+#define NUM_PG_STAT_WALWRITE_ATTS 11
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+	Datum		values[NUM_PG_STAT_WALWRITE_ATTS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_ATTS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->writes);
+	values[1] = Int64GetDatum(walwrite_stats->backend_writes);
+	values[2] = Int64GetDatum(walwrite_stats->dirty_writes);
+	values[3] = Int64GetDatum(walwrite_stats->backend_dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->write_blocks);
+	values[5] = Int64GetDatum(walwrite_stats->backend_write_blocks);
+	values[6] = Float8GetDatum(walwrite_stats->total_write_time);
+	values[7] = Float8GetDatum(walwrite_stats->backend_total_write_time);
+	values[8] = Float8GetDatum(walwrite_stats->total_sync_time);
+	values[9] = Float8GetDatum(walwrite_stats->backend_total_sync_time);
+	values[10] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 08b6030..4931559 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -125,6 +125,8 @@ int			max_worker_processes = 8;
 int			max_parallel_workers = 8;
 int			MaxBackends = 0;
 
+bool 		am_autovacuum_worker = false;
+
 int			VacuumCostPageHit = 1;		/* GUC parameters for vacuum */
 int			VacuumCostPageMiss = 10;
 int			VacuumCostPageDirty = 20;
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 79f9b90..2a00d5b 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2914,6 +2914,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3373 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,701,701,701,701,1184}" "{o,o,o,o,o,o,o,o,o,o,o}" "{writes,backend_writes,dirty_writes,backend_dirty_writes,write_blocks,backend_write_blocks,write_time,backend_write_time,sync_time,backend_sync_time,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 4c607b2..386ed06 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -242,6 +242,8 @@ extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 extern PGDLLIMPORT int replacement_sort_tuples;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index e29397f..6c025ff 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -423,6 +425,38 @@ typedef struct PgStat_MsgBgWriter
 } PgStat_MsgBgWriter;
 
 /* ----------
+ * PgStat_MsgWalWrites			Sent by the backend and all background processes/workers
+ *								that does the WAL write operations.
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+
+	PgStat_Counter m_writes;	/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter m_backend_writes;	/* No of writes by backend */
+	PgStat_Counter m_dirty_writes;		/* No of dirty writes by background
+										 * processes/workers when WAL buffers
+										 * full */
+	PgStat_Counter m_backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter m_write_blocks;		/* Total no of pages written by
+										 * background processes/workers */
+	PgStat_Counter m_backend_write_blocks;		/* Total no of pages written
+												 * by backend */
+	PgStat_Counter m_total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter m_backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter m_total_sync_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter m_backend_total_sync_time;	/* Total write time in
+												 * milliseconds by backend */
+}	PgStat_MsgWalWrites;
+
+/* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
  */
@@ -555,6 +589,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +729,33 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter backend_write_blocks;		/* Total no of pages written
+												 * by backend */
+	PgStat_Counter total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter total_sync_time;		/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter backend_total_sync_time;		/* Total write time in
+												 * milliseconds by backend */
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+}	PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1115,6 +1177,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1308,6 +1375,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1322,5 +1390,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif   /* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index d706f42..4c0a55b 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,18 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.backend_write_blocks,
+    a.write_time,
+    a.backend_write_time,
+    a.sync_time,
+    a.backend_sync_time,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, backend_writes, dirty_writes, backend_dirty_writes, write_blocks, backend_write_blocks, write_time, backend_write_time, sync_time, backend_sync_time, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783..8448cac 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index ac339fb..ed833e0 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5732,7 +5732,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         platforms.  You can use the <xref linkend="pgtesttiming"> tool to
         measure the overhead of timing on your system.
         I/O timing information is
-        displayed in <xref linkend="pg-stat-database-view">, in the output of
+        displayed in <xref linkend="pg-stat-database-view">, 
+        <xref linkend="pg-stat-walwrites-view">, in the output of
         <xref linkend="sql-explain"> when the <literal>BUFFERS</> option is
         used, and by <xref linkend="pgstatstatements">.  Only superusers can
         change this setting.
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 9856968..b5ed688 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -357,6 +357,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -2207,6 +2215,108 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+     <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -2986,6 +3096,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 61ca81d..1f474ae 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -860,6 +860,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2109,6 +2110,10 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (am_background_process())
+						LocalWalWritesStats.m_dirty_writes++;
+					else
+						LocalWalWritesStats.m_backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2319,6 +2324,34 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 }
 
 /*
+ * Check whether the current process is a normal backend or not.
+ * This function checks for the background processes that does
+ * some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns FALSE - when the current process is a normal backend
+ *		   TRUE - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (AmBackgroundWriterProcess() ||
+		AmWalWriterProcess() ||
+		AmCheckpointerProcess() ||
+		AmStartupProcess() ||
+		IsBackgroundWorker ||
+		am_walsender ||
+		am_autovacuum_worker)
+	{
+		return true;
+	}
+
+	return false;
+}
+
+/*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
  * If flexible == TRUE, we don't have to write as far as WriteRqst, but
@@ -2341,6 +2374,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2458,6 +2494,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2480,6 +2521,34 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					LocalWalWritesStats.m_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					LocalWalWritesStats.m_backend_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				LocalWalWritesStats.m_total_write_time = 0;
+				LocalWalWritesStats.m_backend_total_write_time = 0;
+			}
+
+			/* check whether writer is a normal backend or not? */
+			if (is_background_process)
+				LocalWalWritesStats.m_writes++;
+			else
+				LocalWalWritesStats.m_backend_writes++;
+
+			if (is_background_process)
+				LocalWalWritesStats.m_write_blocks += npages;
+			else
+				LocalWalWritesStats.m_backend_write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2499,8 +2568,29 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					if (is_background_process)
+						LocalWalWritesStats.m_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+					else
+						LocalWalWritesStats.m_backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+				{
+					LocalWalWritesStats.m_total_sync_time = 0;
+					LocalWalWritesStats.m_backend_total_sync_time = 0;
+				}
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2568,7 +2658,28 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					LocalWalWritesStats.m_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					LocalWalWritesStats.m_backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				LocalWalWritesStats.m_total_sync_time = 0;
+				LocalWalWritesStats.m_backend_total_sync_time = 0;
+			}
 		}
 
 		/* signal that we need to wakeup walsenders later */
@@ -7642,6 +7753,9 @@ StartupXLOG(void)
 		}
 	}
 
+	/* Report WAL write activity now */
+	pgstat_send_walwrites();
+
 	/*
 	 * Preallocate additional log files, if wanted.
 	 */
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index d357c8b..f424c9d 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -891,6 +891,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index 5b43a66..0f3b007 100644
--- a/src/backend/commands/vacuumlazy.c
+++ b/src/backend/commands/vacuumlazy.c
@@ -344,6 +344,8 @@ lazy_vacuum_rel(Relation onerel, int options, VacuumParams *params,
 						 onerel->rd_rel->relisshared,
 						 new_live_tuples,
 						 vacrelstats->new_dead_tuples);
+	/* In case if there is any WAL write activity, send it. */
+	pgstat_send_walwrites();
 	pgstat_progress_end_command();
 
 	/* and log the action if appropriate */
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 33ca749..5a42c69 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -132,7 +132,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index dcb4cf2..1cd623d 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -284,6 +284,7 @@ BackgroundWriterMain(void)
 		 * Send off activity statistics to the stats collector
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		if (FirstCallSinceLastCheckpoint())
 		{
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index fe9041f..8549f8f 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -538,6 +538,7 @@ CheckpointerMain(void)
 		 * stats message types.)
 		 */
 		pgstat_send_bgwriter();
+		pgstat_send_walwrites();
 
 		/*
 		 * Sleep until we are signaled or it's time for another checkpoint or
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 56a8bf2..5400757 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -139,6 +139,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -253,6 +262,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -333,6 +343,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -874,6 +885,9 @@ pgstat_report_stat(bool force)
 
 	/* Now, send function statistics */
 	pgstat_send_funcstats();
+
+	/* Now, send wal writes statistics */
+	pgstat_send_walwrites();
 }
 
 /*
@@ -1300,11 +1314,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2543,6 +2559,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4123,6 +4154,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4339,6 +4403,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4605,6 +4673,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4861,6 +4935,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4868,6 +4943,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4920,6 +4996,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -5208,6 +5294,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5262,6 +5349,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5824,6 +5923,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6004,6 +6109,27 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.writes += msg->m_writes;
+	walwritesStats.backend_writes += msg->m_backend_writes;
+	walwritesStats.dirty_writes += msg->m_dirty_writes;
+	walwritesStats.backend_dirty_writes += msg->m_backend_dirty_writes;
+	walwritesStats.write_blocks += msg->m_write_blocks;
+	walwritesStats.backend_write_blocks += msg->m_backend_write_blocks;
+	walwritesStats.total_write_time += msg->m_total_write_time;
+	walwritesStats.backend_total_write_time += msg->m_backend_total_write_time;
+	walwritesStats.total_sync_time += msg->m_total_sync_time;
+	walwritesStats.backend_total_sync_time += msg->m_backend_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index a575d8f..cf0c279 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index cfc3fba..677473e 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -2106,6 +2106,9 @@ WalSndLoop(WalSndSendDataCallback send_data)
 		/* Send keepalive if the time has come */
 		WalSndKeepaliveIfNecessary(now);
 
+		/* in case if it has any WAL write activity, send now */
+		pgstat_send_walwrites();
+
 		/*
 		 * We don't block if not caught up, unless there is unsent data
 		 * pending in which case we'd better block until the socket is
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index dd2b924..f2d8d50 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1859,3 +1859,42 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 								   heap_form_tuple(tupdesc, values, nulls)));
 }
+
+#define NUM_PG_STAT_WALWRITE_ATTS 11
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+	Datum		values[NUM_PG_STAT_WALWRITE_ATTS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_ATTS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->writes);
+	values[1] = Int64GetDatum(walwrite_stats->backend_writes);
+	values[2] = Int64GetDatum(walwrite_stats->dirty_writes);
+	values[3] = Int64GetDatum(walwrite_stats->backend_dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->write_blocks);
+	values[5] = Int64GetDatum(walwrite_stats->backend_write_blocks);
+	values[6] = Float8GetDatum(walwrite_stats->total_write_time);
+	values[7] = Float8GetDatum(walwrite_stats->backend_total_write_time);
+	values[8] = Float8GetDatum(walwrite_stats->total_sync_time);
+	values[9] = Float8GetDatum(walwrite_stats->backend_total_sync_time);
+	values[10] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 08b6030..4931559 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -125,6 +125,8 @@ int			max_worker_processes = 8;
 int			max_parallel_workers = 8;
 int			MaxBackends = 0;
 
+bool 		am_autovacuum_worker = false;
+
 int			VacuumCostPageHit = 1;		/* GUC parameters for vacuum */
 int			VacuumCostPageMiss = 10;
 int			VacuumCostPageDirty = 20;
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 79f9b90..2a00d5b 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2914,6 +2914,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3373 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,701,701,701,701,1184}" "{o,o,o,o,o,o,o,o,o,o,o}" "{writes,backend_writes,dirty_writes,backend_dirty_writes,write_blocks,backend_write_blocks,write_time,backend_write_time,sync_time,backend_sync_time,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 4c607b2..386ed06 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -242,6 +242,8 @@ extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 extern PGDLLIMPORT int replacement_sort_tuples;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index e29397f..6c025ff 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -423,6 +425,38 @@ typedef struct PgStat_MsgBgWriter
 } PgStat_MsgBgWriter;
 
 /* ----------
+ * PgStat_MsgWalWrites			Sent by the backend and all background processes/workers
+ *								that does the WAL write operations.
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+
+	PgStat_Counter m_writes;	/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter m_backend_writes;	/* No of writes by backend */
+	PgStat_Counter m_dirty_writes;		/* No of dirty writes by background
+										 * processes/workers when WAL buffers
+										 * full */
+	PgStat_Counter m_backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter m_write_blocks;		/* Total no of pages written by
+										 * background processes/workers */
+	PgStat_Counter m_backend_write_blocks;		/* Total no of pages written
+												 * by backend */
+	PgStat_Counter m_total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter m_backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter m_total_sync_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter m_backend_total_sync_time;	/* Total write time in
+												 * milliseconds by backend */
+}	PgStat_MsgWalWrites;
+
+/* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
  */
@@ -555,6 +589,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +729,33 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter backend_write_blocks;		/* Total no of pages written
+												 * by backend */
+	PgStat_Counter total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter total_sync_time;		/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter backend_total_sync_time;		/* Total write time in
+												 * milliseconds by backend */
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+}	PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1115,6 +1177,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1308,6 +1375,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1322,5 +1390,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif   /* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index d706f42..4c0a55b 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,18 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.backend_write_blocks,
+    a.write_time,
+    a.backend_write_time,
+    a.sync_time,
+    a.backend_sync_time,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, backend_writes, dirty_writes, backend_dirty_writes, write_blocks, backend_write_blocks, write_time, backend_write_time, sync_time, backend_sync_time, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783..8448cac 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index ac339fb..ed833e0 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5732,7 +5732,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         platforms.  You can use the <xref linkend="pgtesttiming"> tool to
         measure the overhead of timing on your system.
         I/O timing information is
-        displayed in <xref linkend="pg-stat-database-view">, in the output of
+        displayed in <xref linkend="pg-stat-database-view">, 
+        <xref linkend="pg-stat-walwrites-view">, in the output of
         <xref linkend="sql-explain"> when the <literal>BUFFERS</> option is
         used, and by <xref linkend="pgstatstatements">.  Only superusers can
         change this setting.
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 9856968..b5ed688 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -357,6 +357,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -2207,6 +2215,108 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+     <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -2986,6 +3096,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 5d58f09..a29c108 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -600,6 +600,9 @@ typedef struct XLogCtlData
 	 */
 	XLogwrtResult LogwrtResult;
 
+	/* Protected by WALWriteLock */
+	PgStat_WalWritesCounts stats;
+
 	/*
 	 * Latest initialized page in the cache (last byte position + 1).
 	 *
@@ -860,6 +863,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2109,6 +2113,10 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (am_background_process())
+						XLogCtl->stats.dirty_writes++;
+					else
+						XLogCtl->stats.backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2319,6 +2327,34 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 }
 
 /*
+ * Check whether the current process is a normal backend or not.
+ * This function checks for the background processes that does
+ * some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns FALSE - when the current process is a normal backend
+ *		   TRUE - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (AmBackgroundWriterProcess() ||
+		AmWalWriterProcess() ||
+		AmCheckpointerProcess() ||
+		AmStartupProcess() ||
+		IsBackgroundWorker ||
+		am_walsender ||
+		am_autovacuum_worker)
+	{
+		return true;
+	}
+
+	return false;
+}
+
+/*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
  * If flexible == TRUE, we don't have to write as far as WriteRqst, but
@@ -2341,6 +2377,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2458,6 +2497,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2480,6 +2524,34 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					XLogCtl->stats.total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					XLogCtl->stats.backend_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				XLogCtl->stats.total_write_time = 0;
+				XLogCtl->stats.backend_total_write_time = 0;
+			}
+
+			/* check whether writer is a normal backend or not? */
+			if (is_background_process)
+				XLogCtl->stats.writes++;
+			else
+				XLogCtl->stats.backend_writes++;
+
+			if (is_background_process)
+				XLogCtl->stats.write_blocks += npages;
+			else
+				XLogCtl->stats.backend_write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2499,8 +2571,29 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					if (is_background_process)
+						XLogCtl->stats.total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+					else
+						XLogCtl->stats.backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+				{
+					XLogCtl->stats.total_sync_time = 0;
+					XLogCtl->stats.backend_total_sync_time = 0;
+				}
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2568,7 +2661,28 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					XLogCtl->stats.total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					XLogCtl->stats.backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				XLogCtl->stats.total_sync_time = 0;
+				XLogCtl->stats.backend_total_sync_time = 0;
+			}
 		}
 
 		/* signal that we need to wakeup walsenders later */
@@ -3043,6 +3157,9 @@ XLogBackgroundFlush(void)
 	{
 		XLogWrite(WriteRqst, flexible);
 	}
+
+	/* Collect all the wal write shared counters into local, and report it to stats collector */
+	memcpy(&LocalWalWritesStats.stats, &XLogCtl->stats, sizeof(PgStat_WalWritesCounts));
 	LWLockRelease(WALWriteLock);
 
 	END_CRIT_SECTION();
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index d357c8b..f424c9d 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -891,6 +891,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 33ca749..5a42c69 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -132,7 +132,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 56a8bf2..cdb1e9f 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -139,6 +139,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -253,6 +262,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -333,6 +343,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -1300,11 +1311,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2543,6 +2556,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4123,6 +4151,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4339,6 +4400,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4605,6 +4670,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4861,6 +4932,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4868,6 +4940,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4920,6 +4993,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -5208,6 +5291,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5262,6 +5346,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5824,6 +5920,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6004,6 +6106,27 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.stats.writes += msg->stats.writes;
+	walwritesStats.stats.backend_writes += msg->stats.backend_writes;
+	walwritesStats.stats.dirty_writes += msg->stats.dirty_writes;
+	walwritesStats.stats.backend_dirty_writes += msg->stats.backend_dirty_writes;
+	walwritesStats.stats.write_blocks += msg->stats.write_blocks;
+	walwritesStats.stats.backend_write_blocks += msg->stats.backend_write_blocks;
+	walwritesStats.stats.total_write_time += msg->stats.total_write_time;
+	walwritesStats.stats.backend_total_write_time += msg->stats.backend_total_write_time;
+	walwritesStats.stats.total_sync_time += msg->stats.total_sync_time;
+	walwritesStats.stats.backend_total_sync_time += msg->stats.backend_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index a575d8f..cf0c279 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index dd2b924..6c8c934 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1859,3 +1859,42 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 								   heap_form_tuple(tupdesc, values, nulls)));
 }
+
+#define NUM_PG_STAT_WALWRITE_ATTS 11
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+	Datum		values[NUM_PG_STAT_WALWRITE_ATTS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_ATTS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->stats.writes);
+	values[1] = Int64GetDatum(walwrite_stats->stats.backend_writes);
+	values[2] = Int64GetDatum(walwrite_stats->stats.dirty_writes);
+	values[3] = Int64GetDatum(walwrite_stats->stats.backend_dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->stats.write_blocks);
+	values[5] = Int64GetDatum(walwrite_stats->stats.backend_write_blocks);
+	values[6] = Float8GetDatum(walwrite_stats->stats.total_write_time);
+	values[7] = Float8GetDatum(walwrite_stats->stats.backend_total_write_time);
+	values[8] = Float8GetDatum(walwrite_stats->stats.total_sync_time);
+	values[9] = Float8GetDatum(walwrite_stats->stats.backend_total_sync_time);
+	values[10] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 08b6030..4931559 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -125,6 +125,8 @@ int			max_worker_processes = 8;
 int			max_parallel_workers = 8;
 int			MaxBackends = 0;
 
+bool 		am_autovacuum_worker = false;
+
 int			VacuumCostPageHit = 1;		/* GUC parameters for vacuum */
 int			VacuumCostPageMiss = 10;
 int			VacuumCostPageDirty = 20;
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 220ba7b..04f42b1 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2916,6 +2916,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3373 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,701,701,701,701,1184}" "{o,o,o,o,o,o,o,o,o,o,o}" "{writes,backend_writes,dirty_writes,backend_dirty_writes,write_blocks,backend_write_blocks,write_time,backend_write_time,sync_time,backend_sync_time,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 4c607b2..386ed06 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -242,6 +242,8 @@ extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 extern PGDLLIMPORT int replacement_sort_tuples;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index e29397f..5680f23 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -422,6 +424,43 @@ typedef struct PgStat_MsgBgWriter
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgBgWriter;
 
+/*
+ * Walwrites statistics counters
+ */
+typedef struct PgStat_WalWritesCounts
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter backend_write_blocks;		/* Total no of pages written
+												 * by backend */
+	PgStat_Counter total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter total_sync_time;		/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter backend_total_sync_time;		/* Total write time in
+												 * milliseconds by backend */
+} PgStat_WalWritesCounts;
+
+/* ----------
+ * PgStat_MsgWalWrites			Sent by the walwriter after collecting all shared stats
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_WalWritesCounts stats;
+} PgStat_MsgWalWrites;
+
 /* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
@@ -555,6 +594,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +734,14 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_WalWritesCounts stats;
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+} PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1115,6 +1163,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1308,6 +1361,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1322,5 +1376,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif   /* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index d706f42..4c0a55b 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,18 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.backend_write_blocks,
+    a.write_time,
+    a.backend_write_time,
+    a.sync_time,
+    a.backend_sync_time,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, backend_writes, dirty_writes, backend_dirty_writes, write_blocks, backend_write_blocks, write_time, backend_write_time, sync_time, backend_sync_time, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783..8448cac 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';

From bf121d038d97bcd53344f5757f533aa3ad716e73 Mon Sep 17 00:00:00 2001
From: Hari Babu <haribabuk@fast.au.fujitsu.com>
Date: Tue, 5 Sep 2017 11:17:47 +1000
Subject: [PATCH] pg_stat_walwrites statistics view

This view will provide the details of how many blocks,
writes and the time taken to write the WAL data to disk
by the backend, walwriter and other background process.
Based on this data, it is configure walwriter to reduce
the load on the backend processes, thus it should improve
the performance.

The time fields data gets populated only when the
track_io_timing GUC is enabled. This is to avoid adding
some overhead in finding out the time calculation that
is required to report in the view.
---
 doc/src/sgml/config.sgml               |   3 +-
 doc/src/sgml/monitoring.sgml           | 112 ++++++++++++++++++++++++++++
 src/backend/access/transam/xlog.c      | 131 +++++++++++++++++++++++++++++++++
 src/backend/catalog/system_views.sql   |   3 +
 src/backend/postmaster/autovacuum.c    |   1 -
 src/backend/postmaster/pgstat.c        | 130 +++++++++++++++++++++++++++++++-
 src/backend/postmaster/walwriter.c     |   2 +
 src/backend/utils/adt/pgstatfuncs.c    |  44 +++++++++++
 src/backend/utils/init/globals.c       |   1 +
 src/include/catalog/pg_proc.h          |   3 +
 src/include/miscadmin.h                |   2 +
 src/include/pgstat.h                   |  67 ++++++++++++++++-
 src/test/regress/expected/rules.out    |  17 +++++
 src/test/regress/expected/sysviews.out |   7 ++
 src/test/regress/sql/sysviews.sql      |   3 +
 15 files changed, 521 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 5f59a38..85e545d 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5761,7 +5761,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         platforms.  You can use the <xref linkend="pgtesttiming"> tool to
         measure the overhead of timing on your system.
         I/O timing information is
-        displayed in <xref linkend="pg-stat-database-view">, in the output of
+        displayed in <xref linkend="pg-stat-database-view">, 
+        <xref linkend="pg-stat-walwrites-view">, in the output of
         <xref linkend="sql-explain"> when the <literal>BUFFERS</> option is
         used, and by <xref linkend="pgstatstatements">.  Only superusers can
         change this setting.
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 38bf636..8d79a05 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -365,6 +365,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -2254,6 +2262,108 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+     <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -3033,6 +3143,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index df4843f..b612c33 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -598,6 +598,9 @@ typedef struct XLogCtlData
 	 */
 	XLogwrtResult LogwrtResult;
 
+	/* Protected by WALWriteLock */
+	PgStat_WalWritesCounts stats;
+
 	/*
 	 * Latest initialized page in the cache (last byte position + 1).
 	 *
@@ -862,6 +865,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2112,6 +2116,12 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (am_background_process())
+						XLogCtl->stats.dirty_writes++;
+					else if (AmWalWriterProcess())
+						XLogCtl->stats.walwriter_dirty_writes++;
+					else
+						XLogCtl->stats.backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2322,6 +2332,33 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 }
 
 /*
+ * Check whether the current process is a normal backend or not.
+ * This function checks for the background processes that does
+ * some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns false - when the current process is a normal backend
+ *		   true - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (!AmBackgroundWriterProcess() ||
+		!AmCheckpointerProcess() ||
+		!AmStartupProcess() ||
+		!IsBackgroundWorker ||
+		!am_walsender ||
+		!am_autovacuum_worker)
+	{
+		return false;
+	}
+
+	return true;
+}
+
+/*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
  * If flexible == TRUE, we don't have to write as far as WriteRqst, but
@@ -2344,6 +2381,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2461,6 +2501,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2483,6 +2528,41 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					XLogCtl->stats.total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else if (AmWalWriterProcess())
+					XLogCtl->stats.walwriter_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					XLogCtl->stats.backend_total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				XLogCtl->stats.total_write_time = 0;
+				XLogCtl->stats.walwriter_total_write_time = 0;
+				XLogCtl->stats.backend_total_write_time = 0;
+			}
+
+			/* check whether writer is a normal backend or not? */
+			if (is_background_process)
+				XLogCtl->stats.writes++;
+			else if (AmWalWriterProcess())
+				XLogCtl->stats.walwriter_writes++;
+			else
+				XLogCtl->stats.backend_writes++;
+
+			if (is_background_process)
+				XLogCtl->stats.write_blocks += npages;
+			else if (AmWalWriterProcess())
+				XLogCtl->stats.walwriter_write_blocks += npages;
+			else
+				XLogCtl->stats.backend_write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2502,8 +2582,32 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					if (is_background_process)
+						XLogCtl->stats.total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+					else if (AmWalWriterProcess())
+						XLogCtl->stats.walwriter_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+					else
+						XLogCtl->stats.backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+				{
+					XLogCtl->stats.total_sync_time = 0;
+					XLogCtl->stats.walwriter_total_sync_time = 0;
+					XLogCtl->stats.backend_total_sync_time = 0;
+				}
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2571,7 +2675,31 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				if (is_background_process)
+					XLogCtl->stats.total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else if (AmWalWriterProcess())
+					XLogCtl->stats.walwriter_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				else
+					XLogCtl->stats.backend_total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				XLogCtl->stats.total_sync_time = 0;
+				XLogCtl->stats.walwriter_total_sync_time = 0;
+				XLogCtl->stats.backend_total_sync_time = 0;
+			}
 		}
 
 		/* signal that we need to wakeup walsenders later */
@@ -3046,6 +3174,9 @@ XLogBackgroundFlush(void)
 	{
 		XLogWrite(WriteRqst, flexible);
 	}
+
+	/* Collect all the wal write shared counters into local, and report it to stats collector */
+	memcpy(&LocalWalWritesStats.stats, &XLogCtl->stats, sizeof(PgStat_WalWritesCounts));
 	LWLockRelease(WALWriteLock);
 
 	END_CRIT_SECTION();
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index dc40cde..08139a1 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -881,6 +881,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 776b1c0..85e40c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -135,7 +135,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index accf302..95effbd 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -142,6 +142,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -256,6 +265,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -336,6 +346,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -1336,11 +1347,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2580,6 +2593,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4176,6 +4204,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4392,6 +4453,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4658,6 +4723,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4914,6 +4985,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4921,6 +4993,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4985,6 +5058,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -5282,6 +5365,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5336,6 +5420,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5898,6 +5994,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6078,6 +6180,32 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.stats.writes += msg->stats.writes;
+	walwritesStats.stats.walwriter_writes += msg->stats.walwriter_writes;
+	walwritesStats.stats.backend_writes += msg->stats.backend_writes;
+	walwritesStats.stats.dirty_writes += msg->stats.dirty_writes;
+	walwritesStats.stats.walwriter_dirty_writes += msg->stats.walwriter_dirty_writes;
+	walwritesStats.stats.backend_dirty_writes += msg->stats.backend_dirty_writes;
+	walwritesStats.stats.write_blocks += msg->stats.write_blocks;
+	walwritesStats.stats.walwriter_write_blocks += msg->stats.walwriter_write_blocks;
+	walwritesStats.stats.backend_write_blocks += msg->stats.backend_write_blocks;
+	walwritesStats.stats.total_write_time += msg->stats.total_write_time;
+	walwritesStats.stats.walwriter_total_write_time += msg->stats.walwriter_total_write_time;
+	walwritesStats.stats.backend_total_write_time += msg->stats.backend_total_write_time;
+	walwritesStats.stats.total_sync_time += msg->stats.total_sync_time;
+	walwritesStats.stats.walwriter_total_sync_time += msg->stats.walwriter_total_sync_time;
+	walwritesStats.stats.backend_total_sync_time += msg->stats.backend_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 7b89e02..4f4dd84 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 20ce48b..f71e10d 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1861,3 +1861,47 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 									  heap_form_tuple(tupdesc, values, nulls)));
 }
+
+#define NUM_PG_STAT_WALWRITE_ATTS 16
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+	Datum		values[NUM_PG_STAT_WALWRITE_ATTS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_ATTS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->stats.writes);
+	values[1] = Int64GetDatum(walwrite_stats->stats.walwriter_writes);
+	values[2] = Int64GetDatum(walwrite_stats->stats.backend_writes);
+	values[3] = Int64GetDatum(walwrite_stats->stats.dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->stats.walwriter_dirty_writes);
+	values[5] = Int64GetDatum(walwrite_stats->stats.backend_dirty_writes);
+	values[6] = Int64GetDatum(walwrite_stats->stats.write_blocks);
+	values[7] = Int64GetDatum(walwrite_stats->stats.walwriter_write_blocks);
+	values[8] = Int64GetDatum(walwrite_stats->stats.backend_write_blocks);
+	values[9] = Float8GetDatum(walwrite_stats->stats.total_write_time);
+	values[10] = Float8GetDatum(walwrite_stats->stats.walwriter_total_write_time);
+	values[11] = Float8GetDatum(walwrite_stats->stats.backend_total_write_time);
+	values[12] = Float8GetDatum(walwrite_stats->stats.total_sync_time);
+	values[13] = Float8GetDatum(walwrite_stats->stats.walwriter_total_sync_time);
+	values[14] = Float8GetDatum(walwrite_stats->stats.backend_total_sync_time);
+	values[15] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 7c09498..3cb2b54 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -101,6 +101,7 @@ bool		IsPostmasterEnvironment = false;
 bool		IsUnderPostmaster = false;
 bool		IsBinaryUpgrade = false;
 bool		IsBackgroundWorker = false;
+bool            am_autovacuum_worker = false;
 
 bool		ExitOnAnyError = false;
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index d820b56..e1a61bc 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2973,6 +2973,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3998 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,20,20,20,701,701,701,701,701,701,1184}" "{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}" "{writes,walwriter_writes,backend_writes,dirty_writes,walwriter_dirty_writes,backend_dirty_writes,write_blocks,walwriter_write_blocks,backend_write_blocks,write_time,walwriter_write_time,backend_write_time,sync_time,walwriter_sync_time,backend_sync_time,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index dad98de..201c8e6 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -243,6 +243,8 @@ extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 extern PGDLLIMPORT int replacement_sort_tuples;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 57ac5d4..b4d1fca 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -422,6 +424,50 @@ typedef struct PgStat_MsgBgWriter
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgBgWriter;
 
+/*
+ * Walwrites statistics counters
+ */
+typedef struct PgStat_WalWritesCounts
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter walwriter_writes;		/* No of writes by walwriter */
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter walwriter_dirty_writes;/* No of dirty writes by walwriter
+	 	 	 	 	 	 	 	 	 	   * when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter walwriter_write_blocks;/* Total no of pages written by walwriter */
+	PgStat_Counter backend_write_blocks;	/* Total no of pages written by backend */
+	PgStat_Counter total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter walwriter_total_write_time;	/* Total write time in milliseconds by
+										 	 	 * walwriter */
+	PgStat_Counter backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter total_sync_time;		/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter walwriter_total_sync_time;		/* Total write time in milliseconds by
+										 	 	 	 * walwriter */
+	PgStat_Counter backend_total_sync_time;		/* Total write time in
+												 * milliseconds by backend */
+} PgStat_WalWritesCounts;
+
+/* ----------
+ * PgStat_MsgWalWrites			Sent by the walwriter after collecting all shared stats
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_WalWritesCounts stats;
+} PgStat_MsgWalWrites;
+
 /* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
@@ -555,6 +601,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +741,14 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_WalWritesCounts stats;
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+} PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1120,6 +1175,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1313,6 +1373,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1327,5 +1388,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif							/* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index d582bc9..996de8a 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,23 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.walwriter_writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.walwriter_dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.walwriter_write_blocks,
+    a.backend_write_blocks,
+    a.write_time,
+    a.walwriter_write_time,
+    a.backend_write_time,
+    a.sync_time,
+    a.walwriter_sync_time,
+    a.backend_sync_time,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, walwriter_writes, backend_writes, dirty_writes, walwriter_dirty_writes, backend_dirty_writes, write_blocks, walwriter_write_blocks, backend_write_blocks, write_time, walwriter_write_time, backend_write_time, sync_time, walwriter_sync_time, backend_sync_time, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783..8448cac 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
-- 
2.7.4.windows.1

From bbd7c4bf2f7327c23ce67b385cd833dba68586a2 Mon Sep 17 00:00:00 2001
From: Hari Babu <haribabuk@fast.au.fujitsu.com>
Date: Tue, 5 Sep 2017 11:17:47 +1000
Subject: [PATCH] pg_stat_walwrites statistics view

This view will provide the details of how many blocks,
writes and the time taken to write the WAL data to disk
by the backend, walwriter and other background process.
Based on this data, it is configure walwriter to reduce
the load on the backend processes, thus it should improve
the performance.

The time fields data gets populated only when the
track_io_timing GUC is enabled. This is to avoid adding
some overhead in finding out the time calculation that
is required to report in the view.
---
 doc/src/sgml/config.sgml               |   3 +-
 doc/src/sgml/monitoring.sgml           | 112 ++++++++++++++++++++++++++++
 src/backend/access/transam/xlog.c      | 126 ++++++++++++++++++++++++++++++++
 src/backend/catalog/system_views.sql   |   3 +
 src/backend/postmaster/autovacuum.c    |   1 -
 src/backend/postmaster/pgstat.c        | 130 ++++++++++++++++++++++++++++++++-
 src/backend/postmaster/walwriter.c     |   2 +
 src/backend/utils/adt/pgstatfuncs.c    |  44 +++++++++++
 src/backend/utils/init/globals.c       |   1 +
 src/include/catalog/pg_proc.h          |   3 +
 src/include/miscadmin.h                |   2 +
 src/include/pgstat.h                   |  67 ++++++++++++++++-
 src/test/regress/expected/rules.out    |  17 +++++
 src/test/regress/expected/sysviews.out |   7 ++
 src/test/regress/sql/sysviews.sql      |   3 +
 15 files changed, 516 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 5f59a38..85e545d 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5761,7 +5761,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         platforms.  You can use the <xref linkend="pgtesttiming"> tool to
         measure the overhead of timing on your system.
         I/O timing information is
-        displayed in <xref linkend="pg-stat-database-view">, in the output of
+        displayed in <xref linkend="pg-stat-database-view">, 
+        <xref linkend="pg-stat-walwrites-view">, in the output of
         <xref linkend="sql-explain"> when the <literal>BUFFERS</> option is
         used, and by <xref linkend="pgstatstatements">.  Only superusers can
         change this setting.
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 38bf636..8d79a05 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -365,6 +365,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -2254,6 +2262,108 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+     <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -3033,6 +3143,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index a3e8ce0..00814fe 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -598,6 +598,9 @@ typedef struct XLogCtlData
 	 */
 	XLogwrtResult LogwrtResult;
 
+	/* Protected by WALWriteLock */
+	PgStat_WalWritesCounts stats;
+
 	/*
 	 * Latest initialized page in the cache (last byte position + 1).
 	 *
@@ -862,6 +865,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2112,6 +2116,12 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (am_background_process())
+						XLogCtl->stats.dirty_writes++;
+					else if (AmWalWriterProcess())
+						XLogCtl->stats.walwriter_dirty_writes++;
+					else
+						XLogCtl->stats.backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2322,6 +2332,33 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 }
 
 /*
+ * Check whether the current process is a normal backend or not.
+ * This function checks for the background processes that does
+ * some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns false - when the current process is a normal backend
+ *		   true - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (!AmBackgroundWriterProcess() ||
+		!AmCheckpointerProcess() ||
+		!AmStartupProcess() ||
+		!IsBackgroundWorker ||
+		!am_walsender ||
+		!am_autovacuum_worker)
+	{
+		return false;
+	}
+
+	return true;
+}
+
+/*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
  * If flexible == TRUE, we don't have to write as far as WriteRqst, but
@@ -2344,6 +2381,13 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
+	PgStat_Counter writes = 0;
+	PgStat_Counter write_blocks = 0;
+	PgStat_Counter total_write_time = 0;
+	PgStat_Counter total_sync_time = 0;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2461,6 +2505,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2483,6 +2532,24 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				total_write_time = 0;
+			}
+
+			/* check whether writer is a normal backend or not? */
+			writes++;
+			write_blocks += npages;
+
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2502,8 +2569,25 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+				{
+					total_sync_time = 0;
+				}
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2571,7 +2655,24 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				total_sync_time = 0;
+			}
 		}
 
 		/* signal that we need to wakeup walsenders later */
@@ -2580,6 +2681,28 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 		LogwrtResult.Flush = LogwrtResult.Write;
 	}
 
+	if (is_background_process)
+	{
+		XLogCtl->stats.writes += writes;
+		XLogCtl->stats.write_blocks += write_blocks;
+		XLogCtl->stats.total_write_time += total_write_time;
+		XLogCtl->stats.total_sync_time += total_sync_time;
+	}
+	else if (AmWalWriterProcess())
+	{
+		XLogCtl->stats.walwriter_writes += writes;
+		XLogCtl->stats.walwriter_write_blocks += write_blocks;
+		XLogCtl->stats.walwriter_total_write_time += total_write_time;
+		XLogCtl->stats.walwriter_total_sync_time += total_sync_time;
+	}
+	else
+	{
+		XLogCtl->stats.backend_writes += writes;
+		XLogCtl->stats.backend_write_blocks += write_blocks;
+		XLogCtl->stats.backend_total_write_time += total_write_time;
+		XLogCtl->stats.backend_total_sync_time += total_sync_time;
+	}
+
 	/*
 	 * Update shared-memory status
 	 *
@@ -3046,6 +3169,9 @@ XLogBackgroundFlush(void)
 	{
 		XLogWrite(WriteRqst, flexible);
 	}
+
+	/* Collect all the wal write shared counters into local, and report it to stats collector */
+	memcpy(&LocalWalWritesStats.stats, &XLogCtl->stats, sizeof(PgStat_WalWritesCounts));
 	LWLockRelease(WALWriteLock);
 
 	END_CRIT_SECTION();
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index dc40cde..08139a1 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -881,6 +881,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 776b1c0..85e40c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -135,7 +135,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index accf302..95effbd 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -142,6 +142,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -256,6 +265,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -336,6 +346,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -1336,11 +1347,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2580,6 +2593,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4176,6 +4204,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4392,6 +4453,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4658,6 +4723,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4914,6 +4985,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4921,6 +4993,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4985,6 +5058,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -5282,6 +5365,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5336,6 +5420,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5898,6 +5994,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6078,6 +6180,32 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.stats.writes += msg->stats.writes;
+	walwritesStats.stats.walwriter_writes += msg->stats.walwriter_writes;
+	walwritesStats.stats.backend_writes += msg->stats.backend_writes;
+	walwritesStats.stats.dirty_writes += msg->stats.dirty_writes;
+	walwritesStats.stats.walwriter_dirty_writes += msg->stats.walwriter_dirty_writes;
+	walwritesStats.stats.backend_dirty_writes += msg->stats.backend_dirty_writes;
+	walwritesStats.stats.write_blocks += msg->stats.write_blocks;
+	walwritesStats.stats.walwriter_write_blocks += msg->stats.walwriter_write_blocks;
+	walwritesStats.stats.backend_write_blocks += msg->stats.backend_write_blocks;
+	walwritesStats.stats.total_write_time += msg->stats.total_write_time;
+	walwritesStats.stats.walwriter_total_write_time += msg->stats.walwriter_total_write_time;
+	walwritesStats.stats.backend_total_write_time += msg->stats.backend_total_write_time;
+	walwritesStats.stats.total_sync_time += msg->stats.total_sync_time;
+	walwritesStats.stats.walwriter_total_sync_time += msg->stats.walwriter_total_sync_time;
+	walwritesStats.stats.backend_total_sync_time += msg->stats.backend_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 7b89e02..4f4dd84 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 20ce48b..f71e10d 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1861,3 +1861,47 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 									  heap_form_tuple(tupdesc, values, nulls)));
 }
+
+#define NUM_PG_STAT_WALWRITE_ATTS 16
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+	Datum		values[NUM_PG_STAT_WALWRITE_ATTS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_ATTS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->stats.writes);
+	values[1] = Int64GetDatum(walwrite_stats->stats.walwriter_writes);
+	values[2] = Int64GetDatum(walwrite_stats->stats.backend_writes);
+	values[3] = Int64GetDatum(walwrite_stats->stats.dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->stats.walwriter_dirty_writes);
+	values[5] = Int64GetDatum(walwrite_stats->stats.backend_dirty_writes);
+	values[6] = Int64GetDatum(walwrite_stats->stats.write_blocks);
+	values[7] = Int64GetDatum(walwrite_stats->stats.walwriter_write_blocks);
+	values[8] = Int64GetDatum(walwrite_stats->stats.backend_write_blocks);
+	values[9] = Float8GetDatum(walwrite_stats->stats.total_write_time);
+	values[10] = Float8GetDatum(walwrite_stats->stats.walwriter_total_write_time);
+	values[11] = Float8GetDatum(walwrite_stats->stats.backend_total_write_time);
+	values[12] = Float8GetDatum(walwrite_stats->stats.total_sync_time);
+	values[13] = Float8GetDatum(walwrite_stats->stats.walwriter_total_sync_time);
+	values[14] = Float8GetDatum(walwrite_stats->stats.backend_total_sync_time);
+	values[15] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 7c09498..3cb2b54 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -101,6 +101,7 @@ bool		IsPostmasterEnvironment = false;
 bool		IsUnderPostmaster = false;
 bool		IsBinaryUpgrade = false;
 bool		IsBackgroundWorker = false;
+bool            am_autovacuum_worker = false;
 
 bool		ExitOnAnyError = false;
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index d820b56..e1a61bc 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2973,6 +2973,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3998 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,20,20,20,701,701,701,701,701,701,1184}" "{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}" "{writes,walwriter_writes,backend_writes,dirty_writes,walwriter_dirty_writes,backend_dirty_writes,write_blocks,walwriter_write_blocks,backend_write_blocks,write_time,walwriter_write_time,backend_write_time,sync_time,walwriter_sync_time,backend_sync_time,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index dad98de..201c8e6 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -243,6 +243,8 @@ extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 extern PGDLLIMPORT int replacement_sort_tuples;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 57ac5d4..b4d1fca 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -422,6 +424,50 @@ typedef struct PgStat_MsgBgWriter
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgBgWriter;
 
+/*
+ * Walwrites statistics counters
+ */
+typedef struct PgStat_WalWritesCounts
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter walwriter_writes;		/* No of writes by walwriter */
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter walwriter_dirty_writes;/* No of dirty writes by walwriter
+	 	 	 	 	 	 	 	 	 	   * when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter walwriter_write_blocks;/* Total no of pages written by walwriter */
+	PgStat_Counter backend_write_blocks;	/* Total no of pages written by backend */
+	PgStat_Counter total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter walwriter_total_write_time;	/* Total write time in milliseconds by
+										 	 	 * walwriter */
+	PgStat_Counter backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter total_sync_time;		/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter walwriter_total_sync_time;		/* Total write time in milliseconds by
+										 	 	 	 * walwriter */
+	PgStat_Counter backend_total_sync_time;		/* Total write time in
+												 * milliseconds by backend */
+} PgStat_WalWritesCounts;
+
+/* ----------
+ * PgStat_MsgWalWrites			Sent by the walwriter after collecting all shared stats
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_WalWritesCounts stats;
+} PgStat_MsgWalWrites;
+
 /* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
@@ -555,6 +601,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +741,14 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_WalWritesCounts stats;
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+} PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1120,6 +1175,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1313,6 +1373,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1327,5 +1388,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif							/* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index f1c1b44..6a833de 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,23 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.walwriter_writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.walwriter_dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.walwriter_write_blocks,
+    a.backend_write_blocks,
+    a.write_time,
+    a.walwriter_write_time,
+    a.backend_write_time,
+    a.sync_time,
+    a.walwriter_sync_time,
+    a.backend_sync_time,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, walwriter_writes, backend_writes, dirty_writes, walwriter_dirty_writes, backend_dirty_writes, write_blocks, walwriter_write_blocks, backend_write_blocks, write_time, walwriter_write_time, backend_write_time, sync_time, walwriter_sync_time, backend_sync_time, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783..8448cac 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
-- 
2.7.4.windows.1

From 69b6b325dd07b2a0c1b9a2653ccbdc851e26e2f1 Mon Sep 17 00:00:00 2001
From: Hari Babu <haribabuk@fast.au.fujitsu.com>
Date: Tue, 5 Sep 2017 11:17:47 +1000
Subject: [PATCH] pg_stat_walwrites statistics view

This view will provide the details of how many blocks,
writes and the time taken to write the WAL data to disk
by the backend, walwriter and other background process.
Based on this data, it is configure walwriter to reduce
the load on the backend processes, thus it should improve
the performance.

The time fields data gets populated only when the
track_io_timing GUC is enabled. This is to avoid adding
some overhead in finding out the time calculation that
is required to report in the view.
---
 doc/src/sgml/config.sgml               |   3 +-
 doc/src/sgml/monitoring.sgml           | 112 ++++++++++++++++++++++++++++
 src/backend/access/transam/xlog.c      | 126 ++++++++++++++++++++++++++++++++
 src/backend/catalog/system_views.sql   |   3 +
 src/backend/postmaster/autovacuum.c    |   1 -
 src/backend/postmaster/pgstat.c        | 130 ++++++++++++++++++++++++++++++++-
 src/backend/postmaster/walwriter.c     |   2 +
 src/backend/utils/adt/pgstatfuncs.c    |  44 +++++++++++
 src/backend/utils/init/globals.c       |   1 +
 src/include/catalog/pg_proc.h          |   3 +
 src/include/miscadmin.h                |   2 +
 src/include/pgstat.h                   |  67 ++++++++++++++++-
 src/test/regress/expected/rules.out    |  17 +++++
 src/test/regress/expected/sysviews.out |   7 ++
 src/test/regress/sql/sysviews.sql      |   3 +
 15 files changed, 516 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 5f59a38..85e545d 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5761,7 +5761,8 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
         platforms.  You can use the <xref linkend="pgtesttiming"> tool to
         measure the overhead of timing on your system.
         I/O timing information is
-        displayed in <xref linkend="pg-stat-database-view">, in the output of
+        displayed in <xref linkend="pg-stat-database-view">, 
+        <xref linkend="pg-stat-walwrites-view">, in the output of
         <xref linkend="sql-explain"> when the <literal>BUFFERS</> option is
         used, and by <xref linkend="pgstatstatements">.  Only superusers can
         change this setting.
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 38bf636..8d79a05 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -365,6 +365,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
+     <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
        <xref linkend="pg-stat-database-view"> for details.
@@ -2254,6 +2262,108 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend process</entry>
+     </row>
+     <row>
+     <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+    <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are written to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the background processes/workers, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_sync_time</></entry>
+      <entry><type>double precision</type></entry>
+      <entry>
+      Total amount of time that has been spent in the portion of WAL write processing where files 
+      are synchronized to disk by the backend processes, in milliseconds.
+      This field data will be populated only when the <xref linkend="guc-track-io-timing"> is enabled
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -3033,6 +3143,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index a3e8ce0..3846ea5 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -598,6 +598,9 @@ typedef struct XLogCtlData
 	 */
 	XLogwrtResult LogwrtResult;
 
+	/* Protected by WALWriteLock */
+	PgStat_WalWritesCounts stats;
+
 	/*
 	 * Latest initialized page in the cache (last byte position + 1).
 	 *
@@ -862,6 +865,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2112,6 +2116,12 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (am_background_process())
+						XLogCtl->stats.dirty_writes++;
+					else if (AmWalWriterProcess())
+						XLogCtl->stats.walwriter_dirty_writes++;
+					else
+						XLogCtl->stats.backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2322,6 +2332,33 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 }
 
 /*
+ * Check whether the current process is a background process/worker
+ * or not. This function checks for the background processes that
+ * does some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns false - when the current process is a normal backend
+ *		   true - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (!AmBackgroundWriterProcess() &&
+		!AmCheckpointerProcess() &&
+		!AmStartupProcess() &&
+		!IsBackgroundWorker &&
+		!am_walsender &&
+		!am_autovacuum_worker)
+	{
+		return false;
+	}
+
+	return true;
+}
+
+/*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
  * If flexible == TRUE, we don't have to write as far as WriteRqst, but
@@ -2344,6 +2381,13 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	instr_time	io_start,
+				io_time;
+	PgStat_Counter writes = 0;
+	PgStat_Counter write_blocks = 0;
+	PgStat_Counter total_write_time = 0;
+	PgStat_Counter total_sync_time = 0;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2461,6 +2505,11 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
+			/* Start timer to acquire start time of the wal write */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			nleft = nbytes;
 			do
 			{
@@ -2483,6 +2532,24 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* calculate the total time spent for wal writing */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				total_write_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				total_write_time = 0;
+			}
+
+			/* check whether writer is a normal backend or not? */
+			writes++;
+			write_blocks += npages;
+
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2502,8 +2569,25 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			 */
 			if (finishing_seg)
 			{
+				/* Start timer to acquire start time of the wal sync */
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(io_start);
+
 				issue_xlog_fsync(openLogFile, openLogSegNo);
 
+				/* calculate the total time spent for wal sync */
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(io_time);
+					INSTR_TIME_SUBTRACT(io_time, io_start);
+
+					total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+				}
+				else
+				{
+					total_sync_time = 0;
+				}
+
 				/* signal that we need to wakeup walsenders later */
 				WalSndWakeupRequest();
 
@@ -2571,7 +2655,24 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				openLogOff = 0;
 			}
 
+			/* Start timer to acquire start time of the wal sync */
+			if (track_io_timing)
+				INSTR_TIME_SET_CURRENT(io_start);
+
 			issue_xlog_fsync(openLogFile, openLogSegNo);
+
+			/* calculate the total time spent for wal sync */
+			if (track_io_timing)
+			{
+				INSTR_TIME_SET_CURRENT(io_time);
+				INSTR_TIME_SUBTRACT(io_time, io_start);
+
+				total_sync_time += INSTR_TIME_GET_MILLISEC(io_time);
+			}
+			else
+			{
+				total_sync_time = 0;
+			}
 		}
 
 		/* signal that we need to wakeup walsenders later */
@@ -2580,6 +2681,28 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 		LogwrtResult.Flush = LogwrtResult.Write;
 	}
 
+	if (is_background_process)
+	{
+		XLogCtl->stats.writes += writes;
+		XLogCtl->stats.write_blocks += write_blocks;
+		XLogCtl->stats.total_write_time += total_write_time;
+		XLogCtl->stats.total_sync_time += total_sync_time;
+	}
+	else if (AmWalWriterProcess())
+	{
+		XLogCtl->stats.walwriter_writes += writes;
+		XLogCtl->stats.walwriter_write_blocks += write_blocks;
+		XLogCtl->stats.walwriter_total_write_time += total_write_time;
+		XLogCtl->stats.walwriter_total_sync_time += total_sync_time;
+	}
+	else
+	{
+		XLogCtl->stats.backend_writes += writes;
+		XLogCtl->stats.backend_write_blocks += write_blocks;
+		XLogCtl->stats.backend_total_write_time += total_write_time;
+		XLogCtl->stats.backend_total_sync_time += total_sync_time;
+	}
+
 	/*
 	 * Update shared-memory status
 	 *
@@ -3046,6 +3169,9 @@ XLogBackgroundFlush(void)
 	{
 		XLogWrite(WriteRqst, flexible);
 	}
+
+	/* Collect all the wal write shared counters into local, and report it to stats collector */
+	memcpy(&LocalWalWritesStats.stats, &XLogCtl->stats, sizeof(PgStat_WalWritesCounts));
 	LWLockRelease(WALWriteLock);
 
 	END_CRIT_SECTION();
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index dc40cde..08139a1 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -881,6 +881,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 776b1c0..85e40c8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -135,7 +135,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index accf302..95effbd 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -142,6 +142,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -256,6 +265,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -336,6 +346,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -1336,11 +1347,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2580,6 +2593,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4176,6 +4204,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4392,6 +4453,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4658,6 +4723,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	(void) rc;					/* we'll check for error with ferror */
 
 	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
+	/*
 	 * Walk through the database table.
 	 */
 	hash_seq_init(&hstat, pgStatDBHash);
@@ -4914,6 +4985,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4921,6 +4993,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4985,6 +5058,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	}
 
 	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
+	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
 	 */
@@ -5282,6 +5365,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5336,6 +5420,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5898,6 +5994,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6078,6 +6180,32 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 }
 
 /* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.stats.writes += msg->stats.writes;
+	walwritesStats.stats.walwriter_writes += msg->stats.walwriter_writes;
+	walwritesStats.stats.backend_writes += msg->stats.backend_writes;
+	walwritesStats.stats.dirty_writes += msg->stats.dirty_writes;
+	walwritesStats.stats.walwriter_dirty_writes += msg->stats.walwriter_dirty_writes;
+	walwritesStats.stats.backend_dirty_writes += msg->stats.backend_dirty_writes;
+	walwritesStats.stats.write_blocks += msg->stats.write_blocks;
+	walwritesStats.stats.walwriter_write_blocks += msg->stats.walwriter_write_blocks;
+	walwritesStats.stats.backend_write_blocks += msg->stats.backend_write_blocks;
+	walwritesStats.stats.total_write_time += msg->stats.total_write_time;
+	walwritesStats.stats.walwriter_total_write_time += msg->stats.walwriter_total_write_time;
+	walwritesStats.stats.backend_total_write_time += msg->stats.backend_total_write_time;
+	walwritesStats.stats.total_sync_time += msg->stats.total_sync_time;
+	walwritesStats.stats.walwriter_total_sync_time += msg->stats.walwriter_total_sync_time;
+	walwritesStats.stats.backend_total_sync_time += msg->stats.backend_total_sync_time;
+}
+
+/* ----------
  * pgstat_recv_recoveryconflict() -
  *
  *	Process a RECOVERYCONFLICT message.
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 7b89e02..4f4dd84 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 20ce48b..f71e10d 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1861,3 +1861,47 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 									  heap_form_tuple(tupdesc, values, nulls)));
 }
+
+#define NUM_PG_STAT_WALWRITE_ATTS 16
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+	Datum		values[NUM_PG_STAT_WALWRITE_ATTS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_ATTS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->stats.writes);
+	values[1] = Int64GetDatum(walwrite_stats->stats.walwriter_writes);
+	values[2] = Int64GetDatum(walwrite_stats->stats.backend_writes);
+	values[3] = Int64GetDatum(walwrite_stats->stats.dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->stats.walwriter_dirty_writes);
+	values[5] = Int64GetDatum(walwrite_stats->stats.backend_dirty_writes);
+	values[6] = Int64GetDatum(walwrite_stats->stats.write_blocks);
+	values[7] = Int64GetDatum(walwrite_stats->stats.walwriter_write_blocks);
+	values[8] = Int64GetDatum(walwrite_stats->stats.backend_write_blocks);
+	values[9] = Float8GetDatum(walwrite_stats->stats.total_write_time);
+	values[10] = Float8GetDatum(walwrite_stats->stats.walwriter_total_write_time);
+	values[11] = Float8GetDatum(walwrite_stats->stats.backend_total_write_time);
+	values[12] = Float8GetDatum(walwrite_stats->stats.total_sync_time);
+	values[13] = Float8GetDatum(walwrite_stats->stats.walwriter_total_sync_time);
+	values[14] = Float8GetDatum(walwrite_stats->stats.backend_total_sync_time);
+	values[15] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 7c09498..3cb2b54 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -101,6 +101,7 @@ bool		IsPostmasterEnvironment = false;
 bool		IsUnderPostmaster = false;
 bool		IsBinaryUpgrade = false;
 bool		IsBackgroundWorker = false;
+bool            am_autovacuum_worker = false;
 
 bool		ExitOnAnyError = false;
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index d820b56..e1a61bc 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2973,6 +2973,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3998 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,20,20,20,701,701,701,701,701,701,1184}" "{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}" "{writes,walwriter_writes,backend_writes,dirty_writes,walwriter_dirty_writes,backend_dirty_writes,write_blocks,walwriter_write_blocks,backend_write_blocks,write_time,walwriter_write_time,backend_write_time,sync_time,walwriter_sync_time,backend_sync_time,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index dad98de..201c8e6 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -243,6 +243,8 @@ extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 extern PGDLLIMPORT int replacement_sort_tuples;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 57ac5d4..b4d1fca 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -422,6 +424,50 @@ typedef struct PgStat_MsgBgWriter
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgBgWriter;
 
+/*
+ * Walwrites statistics counters
+ */
+typedef struct PgStat_WalWritesCounts
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter walwriter_writes;		/* No of writes by walwriter */
+	PgStat_Counter backend_writes;		/* No of writes by backend */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter walwriter_dirty_writes;/* No of dirty writes by walwriter
+	 	 	 	 	 	 	 	 	 	   * when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backend when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter walwriter_write_blocks;/* Total no of pages written by walwriter */
+	PgStat_Counter backend_write_blocks;	/* Total no of pages written by backend */
+	PgStat_Counter total_write_time;	/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter walwriter_total_write_time;	/* Total write time in milliseconds by
+										 	 	 * walwriter */
+	PgStat_Counter backend_total_write_time;	/* Total write time in
+												 * milliseconds by backend */
+	PgStat_Counter total_sync_time;		/* Total write time in milliseconds by
+										 * background processes/workers */
+	PgStat_Counter walwriter_total_sync_time;		/* Total write time in milliseconds by
+										 	 	 	 * walwriter */
+	PgStat_Counter backend_total_sync_time;		/* Total write time in
+												 * milliseconds by backend */
+} PgStat_WalWritesCounts;
+
+/* ----------
+ * PgStat_MsgWalWrites			Sent by the walwriter after collecting all shared stats
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_WalWritesCounts stats;
+} PgStat_MsgWalWrites;
+
 /* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
@@ -555,6 +601,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +741,14 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_WalWritesCounts stats;
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+} PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1120,6 +1175,11 @@ extern char *pgstat_stat_filename;
 extern PgStat_MsgBgWriter BgWriterStats;
 
 /*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
+/*
  * Updated by pgstat_count_buffer_*_time macros
  */
 extern PgStat_Counter pgStatBlockReadTime;
@@ -1313,6 +1373,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1327,5 +1388,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif							/* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index f1c1b44..6a833de 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,23 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.walwriter_writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.walwriter_dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.walwriter_write_blocks,
+    a.backend_write_blocks,
+    a.write_time,
+    a.walwriter_write_time,
+    a.backend_write_time,
+    a.sync_time,
+    a.walwriter_sync_time,
+    a.backend_sync_time,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, walwriter_writes, backend_writes, dirty_writes, walwriter_dirty_writes, backend_dirty_writes, write_blocks, walwriter_write_blocks, backend_write_blocks, write_time, walwriter_write_time, backend_write_time, sync_time, walwriter_sync_time, backend_sync_time, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783..8448cac 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b..3769880 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) > 0 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
-- 
2.7.4.windows.1

From 10c65fe527734e3c427ef7dd206e5c5173d21cd7 Mon Sep 17 00:00:00 2001
From: Hari Babu <haribabuk@fast.au.fujitsu.com>
Date: Tue, 5 Sep 2017 11:17:47 +1000
Subject: [PATCH] pg_stat_walwrites statistics view

This view will provide the details of how many blocks,
writes and the time taken to write the WAL data to disk
by the backend, walwriter and other background process.
Based on this data, it is configure walwriter to reduce
the load on the backend processes, thus it should improve
the performance.
---
 doc/src/sgml/monitoring.sgml           |  86 +++++++++++++++++++++++
 src/backend/access/transam/xlog.c      |  69 ++++++++++++++++++
 src/backend/catalog/system_views.sql   |   3 +
 src/backend/postmaster/autovacuum.c    |   1 -
 src/backend/postmaster/pgstat.c        | 123 ++++++++++++++++++++++++++++++++-
 src/backend/postmaster/walwriter.c     |   2 +
 src/backend/utils/adt/pgstatfuncs.c    |  36 ++++++++++
 src/backend/utils/init/globals.c       |   1 +
 src/include/catalog/pg_proc.h          |   3 +
 src/include/miscadmin.h                |   2 +
 src/include/pgstat.h                   |  53 +++++++++++++-
 src/test/regress/expected/rules.out    |  10 +++
 src/test/regress/expected/sysviews.out |   7 ++
 src/test/regress/sql/sysviews.sql      |   3 +
 14 files changed, 395 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 18fb9c2aa6..7d0b098a36 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -364,6 +364,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </entry>
      </row>
 
+     <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
      <row>
       <entry><structname>pg_stat_database</><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
@@ -2262,6 +2270,82 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>walwriter_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the wal writer process</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>walwriter_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the wal writer process</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -3041,6 +3125,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</> view.
        Calling <literal>pg_stat_reset_shared('archiver')</> will zero all the
        counters shown in the <structname>pg_stat_archiver</> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index dd028a12a4..c3e6f9eb54 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -600,6 +600,9 @@ typedef struct XLogCtlData
 	 */
 	XLogwrtResult LogwrtResult;
 
+	/* Protected by WALWriteLock */
+	PgStat_WalWritesCounts stats;
+
 	/*
 	 * Latest initialized page in the cache (last byte position + 1).
 	 *
@@ -866,6 +869,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2118,6 +2122,17 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (AmWalWriterProcess())
+					{
+						/*
+						 * Don't consider the writes of wal writer process as dirty writes,
+						 * so skipping.
+						 */
+					}
+					else if (am_background_process())
+						XLogCtl->stats.dirty_writes++;
+					else
+						XLogCtl->stats.backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2331,6 +2346,33 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 	return false;
 }
 
+/*
+ * Check whether the current process is a background process/worker
+ * or not. This function checks for the background processes that
+ * does some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns false - when the current process is a normal backend
+ *		   true - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (!AmBackgroundWriterProcess() &&
+		!AmCheckpointerProcess() &&
+		!AmStartupProcess() &&
+		!IsBackgroundWorker &&
+		!am_walsender &&
+		!am_autovacuum_worker)
+	{
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
@@ -2354,6 +2396,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	PgStat_Counter writes = 0;
+	PgStat_Counter write_blocks = 0;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2475,6 +2520,7 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
 			nleft = nbytes;
 			do
 			{
@@ -2497,6 +2543,10 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* check whether writer is a normal backend or not? */
+			writes++;
+			write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2596,6 +2646,22 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 		LogwrtResult.Flush = LogwrtResult.Write;
 	}
 
+	if (is_background_process)
+	{
+		XLogCtl->stats.writes += writes;
+		XLogCtl->stats.write_blocks += write_blocks;
+	}
+	else if (AmWalWriterProcess())
+	{
+		XLogCtl->stats.walwriter_writes += writes;
+		XLogCtl->stats.walwriter_write_blocks += write_blocks;
+	}
+	else
+	{
+		XLogCtl->stats.backend_writes += writes;
+		XLogCtl->stats.backend_write_blocks += write_blocks;
+	}
+
 	/*
 	 * Update shared-memory status
 	 *
@@ -3063,6 +3129,9 @@ XLogBackgroundFlush(void)
 	{
 		XLogWrite(WriteRqst, flexible);
 	}
+
+	/* Collect all the wal write shared counters into local, and report it to stats collector */
+	memcpy(&LocalWalWritesStats.stats, &XLogCtl->stats, sizeof(PgStat_WalWritesCounts));
 	LWLockRelease(WALWriteLock);
 
 	END_CRIT_SECTION();
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index dc40cde424..08139a14c5 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -881,6 +881,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index db6d91ffdf..18db3aef13 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -135,7 +135,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 3a0b49c7c4..0fc34ae946 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -142,6 +142,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -256,6 +265,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -336,6 +346,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -1336,11 +1347,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2580,6 +2593,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4184,6 +4212,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4400,6 +4461,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4665,6 +4730,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	rc = fwrite(&archiverStats, sizeof(archiverStats), 1, fpout);
 	(void) rc;					/* we'll check for error with ferror */
 
+	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
 	/*
 	 * Walk through the database table.
 	 */
@@ -4922,6 +4993,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4929,6 +5001,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4992,6 +5065,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 		goto done;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
 	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
@@ -5290,6 +5373,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5344,6 +5428,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5906,6 +6002,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6085,6 +6187,25 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 	globalStats.buf_alloc += msg->m_buf_alloc;
 }
 
+/* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.stats.writes += msg->stats.writes;
+	walwritesStats.stats.walwriter_writes += msg->stats.walwriter_writes;
+	walwritesStats.stats.backend_writes += msg->stats.backend_writes;
+	walwritesStats.stats.dirty_writes += msg->stats.dirty_writes;
+	walwritesStats.stats.backend_dirty_writes += msg->stats.backend_dirty_writes;
+	walwritesStats.stats.write_blocks += msg->stats.write_blocks;
+	walwritesStats.stats.walwriter_write_blocks += msg->stats.walwriter_write_blocks;
+	walwritesStats.stats.backend_write_blocks += msg->stats.backend_write_blocks;
+}
+
 /* ----------
  * pgstat_recv_recoveryconflict() -
  *
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 7b89e02428..4f4dd849f8 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 5a968e3758..ad6c886656 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1870,3 +1870,39 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 									  heap_form_tuple(tupdesc, values, nulls)));
 }
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+#define NUM_PG_STAT_WALWRITE_COLS 9
+	Datum		values[NUM_PG_STAT_WALWRITE_COLS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_COLS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->stats.writes);
+	values[1] = Int64GetDatum(walwrite_stats->stats.walwriter_writes);
+	values[2] = Int64GetDatum(walwrite_stats->stats.backend_writes);
+	values[3] = Int64GetDatum(walwrite_stats->stats.dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->stats.backend_dirty_writes);
+	values[5] = Int64GetDatum(walwrite_stats->stats.write_blocks);
+	values[6] = Int64GetDatum(walwrite_stats->stats.walwriter_write_blocks);
+	values[7] = Int64GetDatum(walwrite_stats->stats.backend_write_blocks);
+	values[8] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 7c09498dc0..3cb2b5456f 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -101,6 +101,7 @@ bool		IsPostmasterEnvironment = false;
 bool		IsUnderPostmaster = false;
 bool		IsBinaryUpgrade = false;
 bool		IsBackgroundWorker = false;
+bool            am_autovacuum_worker = false;
 
 bool		ExitOnAnyError = false;
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 93c031aad7..27205f3c9d 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2980,6 +2980,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3998 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,20,20,1184}" "{o,o,o,o,o,o,o,o,o}" "{writes,walwriter_writes,backend_writes,dirty_writes,backend_dirty_writes,write_blocks,walwriter_write_blocks,backend_write_blocks,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index dad98de98d..201c8e6217 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -243,6 +243,8 @@ extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 extern PGDLLIMPORT int replacement_sort_tuples;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 089b7c3a10..5be0b062ca 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -422,6 +424,36 @@ typedef struct PgStat_MsgBgWriter
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgBgWriter;
 
+/*
+ * Walwrites statistics counters
+ */
+typedef struct PgStat_WalWritesCounts
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter walwriter_writes;		/* No of writes by walwriter */
+	PgStat_Counter backend_writes;		/* No of writes by backends */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backends when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter walwriter_write_blocks;/* Total no of pages written by walwriter */
+	PgStat_Counter backend_write_blocks;	/* Total no of pages written by backends */
+} PgStat_WalWritesCounts;
+
+/* ----------
+ * PgStat_MsgWalWrites			Sent by the walwriter after collecting all shared stats
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_WalWritesCounts stats;
+} PgStat_MsgWalWrites;
+
 /* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
@@ -555,6 +587,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +727,14 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_WalWritesCounts stats;
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+} PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1125,6 +1166,11 @@ extern char *pgstat_stat_filename;
  */
 extern PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
 /*
  * Updated by pgstat_count_buffer_*_time macros
  */
@@ -1321,6 +1367,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1335,5 +1382,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif							/* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index f1c1b44d6f..6a84e3f980 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,16 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.walwriter_writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.walwriter_write_blocks,
+    a.backend_write_blocks,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, walwriter_writes, backend_writes, dirty_writes, backend_dirty_writes, write_blocks, walwriter_write_blocks, backend_write_blocks, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 568b783f5e..aa91df0a6c 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) = 1 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b735..21f49c9a3b 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) = 1 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
-- 
2.14.1.windows.1

From 43ba7bf73e60f92022e5c32ed546567be6d3f9c8 Mon Sep 17 00:00:00 2001
From: Hari Babu <haribabuk@fast.au.fujitsu.com>
Date: Tue, 5 Sep 2017 11:17:47 +1000
Subject: [PATCH] pg_stat_walwrites statistics view

This view will provide the details of how many blocks,
writes and the time taken to write the WAL data to disk
by the backend, walwriter and other background process.
Based on this data, it is configure walwriter to reduce
the load on the backend processes, thus it should improve
the performance.
---
 doc/src/sgml/monitoring.sgml           |  86 +++++++++++++++++++++++
 src/backend/access/transam/xlog.c      |  69 ++++++++++++++++++
 src/backend/catalog/system_views.sql   |   3 +
 src/backend/postmaster/autovacuum.c    |   1 -
 src/backend/postmaster/pgstat.c        | 123 ++++++++++++++++++++++++++++++++-
 src/backend/postmaster/walwriter.c     |   2 +
 src/backend/utils/adt/pgstatfuncs.c    |  36 ++++++++++
 src/backend/utils/init/globals.c       |   1 +
 src/include/catalog/pg_proc.h          |   3 +
 src/include/miscadmin.h                |   2 +
 src/include/pgstat.h                   |  53 +++++++++++++-
 src/test/regress/expected/rules.out    |  10 +++
 src/test/regress/expected/sysviews.out |   7 ++
 src/test/regress/sql/sysviews.sql      |   3 +
 14 files changed, 395 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 6f8203355e..f91de9c5da 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -364,6 +364,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </entry>
      </row>
 
+     <row>
+      <entry><structname>pg_stat_walwrites</><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"> for details.
+     </entry>
+     </row>
+
      <row>
       <entry><structname>pg_stat_database</structname><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
@@ -2262,6 +2270,82 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>walwriter_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the wal writer process</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"> are full.
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_dirty_writes</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>walwriter_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the wal writer process</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -3041,6 +3125,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</structname> view.
        Calling <literal>pg_stat_reset_shared('archiver')</literal> will zero all the
        counters shown in the <structname>pg_stat_archiver</structname> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</literal> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</structname> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index dd028a12a4..c3e6f9eb54 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -600,6 +600,9 @@ typedef struct XLogCtlData
 	 */
 	XLogwrtResult LogwrtResult;
 
+	/* Protected by WALWriteLock */
+	PgStat_WalWritesCounts stats;
+
 	/*
 	 * Latest initialized page in the cache (last byte position + 1).
 	 *
@@ -866,6 +869,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2118,6 +2122,17 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (AmWalWriterProcess())
+					{
+						/*
+						 * Don't consider the writes of wal writer process as dirty writes,
+						 * so skipping.
+						 */
+					}
+					else if (am_background_process())
+						XLogCtl->stats.dirty_writes++;
+					else
+						XLogCtl->stats.backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2331,6 +2346,33 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 	return false;
 }
 
+/*
+ * Check whether the current process is a background process/worker
+ * or not. This function checks for the background processes that
+ * does some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns false - when the current process is a normal backend
+ *		   true - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (!AmBackgroundWriterProcess() &&
+		!AmCheckpointerProcess() &&
+		!AmStartupProcess() &&
+		!IsBackgroundWorker &&
+		!am_walsender &&
+		!am_autovacuum_worker)
+	{
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
@@ -2354,6 +2396,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	PgStat_Counter writes = 0;
+	PgStat_Counter write_blocks = 0;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2475,6 +2520,7 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
 			nbytes = npages * (Size) XLOG_BLCKSZ;
+
 			nleft = nbytes;
 			do
 			{
@@ -2497,6 +2543,10 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* check whether writer is a normal backend or not? */
+			writes++;
+			write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2596,6 +2646,22 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 		LogwrtResult.Flush = LogwrtResult.Write;
 	}
 
+	if (is_background_process)
+	{
+		XLogCtl->stats.writes += writes;
+		XLogCtl->stats.write_blocks += write_blocks;
+	}
+	else if (AmWalWriterProcess())
+	{
+		XLogCtl->stats.walwriter_writes += writes;
+		XLogCtl->stats.walwriter_write_blocks += write_blocks;
+	}
+	else
+	{
+		XLogCtl->stats.backend_writes += writes;
+		XLogCtl->stats.backend_write_blocks += write_blocks;
+	}
+
 	/*
 	 * Update shared-memory status
 	 *
@@ -3063,6 +3129,9 @@ XLogBackgroundFlush(void)
 	{
 		XLogWrite(WriteRqst, flexible);
 	}
+
+	/* Collect all the wal write shared counters into local, and report it to stats collector */
+	memcpy(&LocalWalWritesStats.stats, &XLogCtl->stats, sizeof(PgStat_WalWritesCounts));
 	LWLockRelease(WALWriteLock);
 
 	END_CRIT_SECTION();
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index dc40cde424..08139a14c5 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -881,6 +881,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 48765bb01b..5fbcbcc0a9 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -136,7 +136,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 3a0b49c7c4..0fc34ae946 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -142,6 +142,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_MsgWalWrites LocalWalWritesStats;
+
 /* ----------
  * Local data
  * ----------
@@ -256,6 +265,7 @@ static int	localNumBackends = 0;
  */
 static PgStat_ArchiverStats archiverStats;
 static PgStat_GlobalStats globalStats;
+static PgStat_WalWritesStats walwritesStats;
 
 /*
  * List of OIDs of databases we need to write out.  If an entry is InvalidOid,
@@ -336,6 +346,7 @@ static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
 static void pgstat_recv_recoveryconflict(PgStat_MsgRecoveryConflict *msg, int len);
 static void pgstat_recv_deadlock(PgStat_MsgDeadlock *msg, int len);
 static void pgstat_recv_tempfile(PgStat_MsgTempFile *msg, int len);
+static void pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len);
 
 /* ------------------------------------------------------------
  * Public functions called from postmaster follow
@@ -1336,11 +1347,13 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+		msg.m_resettarget = RESET_WALWRITES;
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
@@ -2580,6 +2593,21 @@ pgstat_fetch_global(void)
 	return &globalStats;
 }
 
+/*
+ * ---------
+ * pgstat_fetch_stat_walwrites() -
+ *
+ *	Support function for the SQL-callable pgstat* functions. Returns
+ *	a pointer to the walwrites statistics struct.
+ * ---------
+ */
+PgStat_WalWritesStats *
+pgstat_fetch_stat_walwrites(void)
+{
+	backend_read_statsfile();
+
+	return &walwritesStats;
+}
 
 /* ------------------------------------------------------------
  * Functions for management of the shared-memory PgBackendStatus array
@@ -4184,6 +4212,39 @@ pgstat_send_bgwriter(void)
 	MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
 }
 
+/* ----------
+ * pgstat_send_walwrites() -
+ *
+ *		Send wal writes statistics to the collector
+ * ----------
+ */
+
+void
+pgstat_send_walwrites(void)
+{
+	/* We assume this initializes to zeroes */
+	static const PgStat_MsgWalWrites all_zeroes;
+
+	/*
+	 * This function can be called even if nothing at all has happened. In
+	 * this case, avoid sending a completely empty message to the stats
+	 * collector.
+	 */
+	if (memcmp(&LocalWalWritesStats, &all_zeroes, sizeof(PgStat_MsgWalWrites)) == 0)
+		return;
+
+	/*
+	 * Prepare and send the message
+	 */
+	pgstat_setheader(&LocalWalWritesStats.m_hdr, PGSTAT_MTYPE_WALWRITES);
+	pgstat_send(&LocalWalWritesStats, sizeof(LocalWalWritesStats));
+
+	/*
+	 * Clear out the statistics buffer, so it can be re-used.
+	 */
+	MemSet(&LocalWalWritesStats, 0, sizeof(LocalWalWritesStats));
+}
+
 
 /* ----------
  * PgstatCollectorMain() -
@@ -4400,6 +4461,10 @@ PgstatCollectorMain(int argc, char *argv[])
 					pgstat_recv_tempfile((PgStat_MsgTempFile *) &msg, len);
 					break;
 
+				case PGSTAT_MTYPE_WALWRITES:
+					pgstat_recv_walwrites((PgStat_MsgWalWrites *) & msg, len);
+					break;
+
 				default:
 					break;
 			}
@@ -4665,6 +4730,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs)
 	rc = fwrite(&archiverStats, sizeof(archiverStats), 1, fpout);
 	(void) rc;					/* we'll check for error with ferror */
 
+	/*
+	 * Write wal writes stats struct
+	 */
+	rc = fwrite(&walwritesStats, sizeof(walwritesStats), 1, fpout);
+	(void) rc;					/* we'll check for error with ferror */
+
 	/*
 	 * Walk through the database table.
 	 */
@@ -4922,6 +4993,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	memset(&globalStats, 0, sizeof(globalStats));
 	memset(&archiverStats, 0, sizeof(archiverStats));
+	memset(&walwritesStats, 0, sizeof(walwritesStats));
 
 	/*
 	 * Set the current timestamp (will be kept only in case we can't load an
@@ -4929,6 +5001,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 	 */
 	globalStats.stat_reset_timestamp = GetCurrentTimestamp();
 	archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+	walwritesStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -4992,6 +5065,16 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
 		goto done;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&walwritesStats, 1, sizeof(walwritesStats), fpin) != sizeof(walwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		goto done;
+	}
+
 	/*
 	 * We found an existing collector stats file. Read it and put all the
 	 * hashtable entries into place.
@@ -5290,6 +5373,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 	PgStat_StatDBEntry dbentry;
 	PgStat_GlobalStats myGlobalStats;
 	PgStat_ArchiverStats myArchiverStats;
+	PgStat_WalWritesStats myWalwritesStats;
 	FILE	   *fpin;
 	int32		format_id;
 	const char *statfile = permanent ? PGSTAT_STAT_PERMANENT_FILENAME : pgstat_stat_filename;
@@ -5344,6 +5428,18 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
 		return false;
 	}
 
+	/*
+	 * Read wal writes stats struct
+	 */
+	if (fread(&myWalwritesStats, 1, sizeof(myWalwritesStats),
+			  fpin) != sizeof(myWalwritesStats))
+	{
+		ereport(pgStatRunningInCollector ? LOG : WARNING,
+				(errmsg("corrupted statistics file \"%s\"", statfile)));
+		FreeFile(fpin);
+		return false;
+	}
+
 	/* By default, we're going to return the timestamp of the global file. */
 	*ts = myGlobalStats.stats_timestamp;
 
@@ -5906,6 +6002,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 		memset(&archiverStats, 0, sizeof(archiverStats));
 		archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
 	}
+	else if (msg->m_resettarget == RESET_WALWRITES)
+	{
+		/* Reset the wal writes statistics of the cluster. */
+		memset(&walwritesStats, 0, sizeof(walwritesStats));
+		walwritesStats.stat_reset_timestamp = GetCurrentTimestamp();
+	}
 
 	/*
 	 * Presumably the sender of this message validated the target, don't
@@ -6085,6 +6187,25 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 	globalStats.buf_alloc += msg->m_buf_alloc;
 }
 
+/* ----------
+ * pgstat_recv_walwrites() -
+ *
+ *	Process a WALWRITES message.
+ * ----------
+ */
+static void
+pgstat_recv_walwrites(PgStat_MsgWalWrites * msg, int len)
+{
+	walwritesStats.stats.writes += msg->stats.writes;
+	walwritesStats.stats.walwriter_writes += msg->stats.walwriter_writes;
+	walwritesStats.stats.backend_writes += msg->stats.backend_writes;
+	walwritesStats.stats.dirty_writes += msg->stats.dirty_writes;
+	walwritesStats.stats.backend_dirty_writes += msg->stats.backend_dirty_writes;
+	walwritesStats.stats.write_blocks += msg->stats.write_blocks;
+	walwritesStats.stats.walwriter_write_blocks += msg->stats.walwriter_write_blocks;
+	walwritesStats.stats.backend_write_blocks += msg->stats.backend_write_blocks;
+}
+
 /* ----------
  * pgstat_recv_recoveryconflict() -
  *
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 7b89e02428..4f4dd849f8 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -280,6 +280,8 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		pgstat_send_walwrites();
+
 		/*
 		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
 		 * haven't done anything useful for quite some time, lengthen the
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 8d9e7c10ae..1adca065c7 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1882,3 +1882,39 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 									  heap_form_tuple(tupdesc, values, nulls)));
 }
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+#define NUM_PG_STAT_WALWRITE_COLS 9
+	Datum		values[NUM_PG_STAT_WALWRITE_COLS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_COLS];
+	PgStat_WalWritesStats *walwrite_stats;
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Get statistics about the archiver process */
+	walwrite_stats = pgstat_fetch_stat_walwrites();
+
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(walwrite_stats->stats.writes);
+	values[1] = Int64GetDatum(walwrite_stats->stats.walwriter_writes);
+	values[2] = Int64GetDatum(walwrite_stats->stats.backend_writes);
+	values[3] = Int64GetDatum(walwrite_stats->stats.dirty_writes);
+	values[4] = Int64GetDatum(walwrite_stats->stats.backend_dirty_writes);
+	values[5] = Int64GetDatum(walwrite_stats->stats.write_blocks);
+	values[6] = Int64GetDatum(walwrite_stats->stats.walwriter_write_blocks);
+	values[7] = Int64GetDatum(walwrite_stats->stats.backend_write_blocks);
+	values[8] = TimestampTzGetDatum(walwrite_stats->stat_reset_timestamp);
+
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+								   heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 9680a4b0f7..cd09d0da61 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -101,6 +101,7 @@ bool		IsPostmasterEnvironment = false;
 bool		IsUnderPostmaster = false;
 bool		IsBinaryUpgrade = false;
 bool		IsBackgroundWorker = false;
+bool            am_autovacuum_worker = false;
 
 bool		ExitOnAnyError = false;
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 93c031aad7..27205f3c9d 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2980,6 +2980,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3998 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,20,20,1184}" "{o,o,o,o,o,o,o,o,o}" "{writes,walwriter_writes,backend_writes,dirty_writes,backend_dirty_writes,write_blocks,walwriter_write_blocks,backend_write_blocks,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 3950054368..d0a2d6a3d0 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -242,6 +242,8 @@ extern bool allowSystemTableMods;
 extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 
+extern bool	am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 089b7c3a10..5be0b062ca 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -64,7 +64,8 @@ typedef enum StatMsgType
 	PGSTAT_MTYPE_FUNCPURGE,
 	PGSTAT_MTYPE_RECOVERYCONFLICT,
 	PGSTAT_MTYPE_TEMPFILE,
-	PGSTAT_MTYPE_DEADLOCK
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_WALWRITES
 } StatMsgType;
 
 /* ----------
@@ -119,7 +120,8 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER
+	RESET_BGWRITER,
+	RESET_WALWRITES
 } PgStat_Shared_Reset_Target;
 
 /* Possible object types for resetting single counters */
@@ -422,6 +424,36 @@ typedef struct PgStat_MsgBgWriter
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgBgWriter;
 
+/*
+ * Walwrites statistics counters
+ */
+typedef struct PgStat_WalWritesCounts
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter walwriter_writes;		/* No of writes by walwriter */
+	PgStat_Counter backend_writes;		/* No of writes by backends */
+	PgStat_Counter dirty_writes;/* No of dirty writes by background
+								 * processes/workers when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;		/* No of dirty writes by
+												 * backends when WAL buffers
+												 * full */
+	PgStat_Counter write_blocks;/* Total no of pages written by background
+								 * processes/workers */
+	PgStat_Counter walwriter_write_blocks;/* Total no of pages written by walwriter */
+	PgStat_Counter backend_write_blocks;	/* Total no of pages written by backends */
+} PgStat_WalWritesCounts;
+
+/* ----------
+ * PgStat_MsgWalWrites			Sent by the walwriter after collecting all shared stats
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_WalWritesCounts stats;
+} PgStat_MsgWalWrites;
+
 /* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
@@ -555,6 +587,7 @@ typedef union PgStat_Msg
 	PgStat_MsgFuncpurge msg_funcpurge;
 	PgStat_MsgRecoveryConflict msg_recoveryconflict;
 	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgWalWrites msg_walwrites;
 } PgStat_Msg;
 
 
@@ -694,6 +727,14 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_WalWritesCounts stats;
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+} PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1125,6 +1166,11 @@ extern char *pgstat_stat_filename;
  */
 extern PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_MsgWalWrites LocalWalWritesStats;
+
 /*
  * Updated by pgstat_count_buffer_*_time macros
  */
@@ -1321,6 +1367,7 @@ extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
 
 extern void pgstat_send_archiver(const char *xlog, bool failed);
 extern void pgstat_send_bgwriter(void);
+extern void pgstat_send_walwrites(void);
 
 /* ----------
  * Support functions for the SQL-callable functions to
@@ -1335,5 +1382,7 @@ extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
 extern int	pgstat_fetch_stat_numbackends(void);
 extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_WalWritesStats *pgstat_fetch_stat_walwrites(void);
+
 
 #endif							/* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index f1c1b44d6f..6a84e3f980 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,16 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.walwriter_writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.walwriter_write_blocks,
+    a.backend_write_blocks,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, walwriter_writes, backend_writes, dirty_writes, backend_dirty_writes, write_blocks, walwriter_write_blocks, backend_write_blocks, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index cd1f7f301d..40c19838c5 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) = 1 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b735..21f49c9a3b 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) = 1 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
-- 
2.14.2.windows.1

From be6bcf386e92a8b92da3da2c4c59792e9d0e01a4 Mon Sep 17 00:00:00 2001
From: Hari Babu <kommi.haribabu@gmail.com>
Date: Tue, 12 Dec 2017 20:14:16 +1100
Subject: [PATCH] pg_stat_walwrites statistics view

This view will provide the details of how many blocks,
writes and the time taken to write the WAL data to disk
by the backend, walwriter and other background process.
Based on this data, it is configure walwriter to reduce
the load on the backend processes, thus it should improve
the performance.

All the stats are collected and stored in a shared memory
strucuture protected by the WALWriteLock
---
 doc/src/sgml/monitoring.sgml           | 86 ++++++++++++++++++++++++++++++++++
 src/backend/access/transam/xlog.c      | 62 ++++++++++++++++++++++++
 src/backend/catalog/system_views.sql   |  3 ++
 src/backend/postmaster/autovacuum.c    |  1 -
 src/backend/postmaster/pgstat.c        | 48 ++++++++++++++++++-
 src/backend/storage/ipc/ipci.c         |  2 +
 src/backend/utils/adt/pgstatfuncs.c    | 36 ++++++++++++++
 src/backend/utils/init/globals.c       |  1 +
 src/include/catalog/pg_proc.h          |  3 ++
 src/include/miscadmin.h                |  2 +
 src/include/pgstat.h                   | 47 +++++++++++++++++++
 src/test/regress/expected/rules.out    | 10 ++++
 src/test/regress/expected/sysviews.out |  7 +++
 src/test/regress/sql/sysviews.sql      |  3 ++
 14 files changed, 309 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index b6f80d9708..dd2c2cec7e 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -364,6 +364,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </entry>
      </row>
 
+     <row>
+      <entry><structname>pg_stat_walwrites</structname><indexterm><primary>pg_stat_walwrites</primary></indexterm></entry>
+      <entry>One row only, showing statistics about the
+       WAL writing activity. See
+       <xref linkend="pg-stat-walwrites-view"/> for details.
+      </entry>
+     </row>
+
      <row>
       <entry><structname>pg_stat_database</structname><indexterm><primary>pg_stat_database</primary></indexterm></entry>
       <entry>One row per database, showing database-wide statistics. See
@@ -2267,6 +2275,82 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
    single row, containing global data for the cluster.
   </para>
 
+  <table id="pg-stat-walwrites-view" xreflabel="pg_stat_walwrites">
+   <title><structname>pg_stat_walwrites</structname> View</title>
+
+   <tgroup cols="3">
+    <thead>
+     <row>
+      <entry>Column</entry>
+      <entry>Type</entry>
+      <entry>Description</entry>
+     </row>
+    </thead>
+
+    <tbody>
+     <row>
+      <entry><structfield>writes</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of WAL writes that are carried out by background processes and workers. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>walwriter_writes</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the wal writer process</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_writes</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL writes that are carried out by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>dirty_writes</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by background processes and workers
+      when the <xref linkend="guc-wal-buffers"/> are full.
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>backend_dirty_writes</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>
+      Number of dirty WAL writes that are carried out by the backend processes when 
+      the <xref linkend="guc-wal-buffers"/> are full. 
+      </entry>
+     </row>
+     <row>
+      <entry><structfield>write_blocks</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the background processes/workers</entry>
+     </row>
+     <row>
+      <entry><structfield>walwriter_write_blocks</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the wal writer process</entry>
+     </row>
+     <row>
+      <entry><structfield>backend_write_blocks</structfield></entry>
+      <entry><type>bigint</type></entry>
+      <entry>Number of WAL pages written to the disk by the backend processes</entry>
+     </row>
+     <row>
+      <entry><structfield>stats_reset</structfield></entry>
+      <entry><type>timestamp with time zone</type></entry>
+      <entry>Time at which these statistics were last reset</entry>
+     </row>
+     </tbody>
+   </tgroup>
+  </table>
+
+  <para>
+   The <structname>pg_stat_walwrites</structname> view will always have a
+   single row, containing data about the WAL writing activity of the cluster.
+  </para>
+
+
   <table id="pg-stat-database-view" xreflabel="pg_stat_database">
    <title><structname>pg_stat_database</structname> View</title>
    <tgroup cols="3">
@@ -3046,6 +3130,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        counters shown in the <structname>pg_stat_bgwriter</structname> view.
        Calling <literal>pg_stat_reset_shared('archiver')</literal> will zero all the
        counters shown in the <structname>pg_stat_archiver</structname> view.
+       Calling <literal>pg_stat_reset_shared('walwrites')</literal> will zero all the
+       counters shown in the <structname>pg_stat_walwrites</structname> view.
       </entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 0791404263..54f2b1448f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -866,6 +866,7 @@ static XLogRecPtr XLogGetReplicationSlotMinimumLSN(void);
 
 static void AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic);
 static bool XLogCheckpointNeeded(XLogSegNo new_segno);
+static bool am_background_process(void);
 static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible);
 static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
 					   bool find_free, XLogSegNo max_segno,
@@ -2118,6 +2119,17 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
 					WriteRqst.Write = OldPageRqstPtr;
 					WriteRqst.Flush = 0;
 					XLogWrite(WriteRqst, false);
+					if (AmWalWriterProcess())
+					{
+						/*
+						 * Don't consider the writes of wal writer process as
+						 * dirty writes, so skipping.
+						 */
+					}
+					else if (am_background_process())
+						WALWriteStats->stats.dirty_writes++;
+					else
+						WALWriteStats->stats.backend_dirty_writes++;
 					LWLockRelease(WALWriteLock);
 					TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
 				}
@@ -2321,6 +2333,33 @@ XLogCheckpointNeeded(XLogSegNo new_segno)
 	return false;
 }
 
+/*
+ * Check whether the current process is a background process/worker
+ * or not. This function checks for the background processes that
+ * does some WAL write activity only and other background processes
+ * are not considered. It considers all the background workers
+ * as WAL write activity workers.
+ *
+ * Returns false - when the current process is a normal backend
+ *		   true - when the current process a background process/worker
+ */
+static bool
+am_background_process()
+{
+	/* check whether current process is a background process/worker? */
+	if (!AmBackgroundWriterProcess() &&
+		!AmCheckpointerProcess() &&
+		!AmStartupProcess() &&
+		!IsBackgroundWorker &&
+		!am_walsender &&
+		!am_autovacuum_worker)
+	{
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * Write and/or fsync the log at least as far as WriteRqst indicates.
  *
@@ -2344,6 +2383,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 	int			npages;
 	int			startidx;
 	uint32		startoffset;
+	PgStat_Counter writes = 0;
+	PgStat_Counter write_blocks = 0;
+	bool		is_background_process = am_background_process();
 
 	/* We should always be inside a critical section here */
 	Assert(CritSectionCount > 0);
@@ -2487,6 +2529,10 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 				from += written;
 			} while (nleft > 0);
 
+			/* check whether writer is a normal backend or not? */
+			writes++;
+			write_blocks += npages;
+
 			/* Update state for write */
 			openLogOff += nbytes;
 			npages = 0;
@@ -2586,6 +2632,22 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 		LogwrtResult.Flush = LogwrtResult.Write;
 	}
 
+	if (is_background_process)
+	{
+		WALWriteStats->stats.writes += writes;
+		WALWriteStats->stats.write_blocks += write_blocks;
+	}
+	else if (AmWalWriterProcess())
+	{
+		WALWriteStats->stats.walwriter_writes += writes;
+		WALWriteStats->stats.walwriter_write_blocks += write_blocks;
+	}
+	else
+	{
+		WALWriteStats->stats.backend_writes += writes;
+		WALWriteStats->stats.backend_write_blocks += write_blocks;
+	}
+
 	/*
 	 * Update shared-memory status
 	 *
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 394aea8e0f..9843db1c8b 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -881,6 +881,9 @@ CREATE VIEW pg_stat_bgwriter AS
         pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
+CREATE VIEW pg_stat_walwrites AS
+   SELECT * FROM pg_stat_get_walwrites() AS A;
+
 CREATE VIEW pg_stat_progress_vacuum AS
 	SELECT
 		S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 48765bb01b..5fbcbcc0a9 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -136,7 +136,6 @@ int			Log_autovacuum_min_duration = -1;
 
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
-static bool am_autovacuum_worker = false;
 
 /* Flags set by signal handlers */
 static volatile sig_atomic_t got_SIGHUP = false;
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 5c256ff8ab..202ea9c355 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -142,6 +142,15 @@ char	   *pgstat_stat_tmpname = NULL;
  */
 PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * WalWrites Local statistics counters.
+ * The statistics data gets populated in XLogWrite function.
+ * Stored directly in a stats message structure so it can be sent
+ * to stats collector process without needing to copy things around.
+ * We assume this inits to zeroes.
+ */
+PgStat_WalWritesStats *WALWriteStats;
+
 /* ----------
  * Local data
  * ----------
@@ -630,6 +639,29 @@ startup_failed:
 	SetConfigOption("track_counts", "off", PGC_INTERNAL, PGC_S_OVERRIDE);
 }
 
+/*
+ * Initialization of shared memory for WALWritesStats
+ */
+Size
+WALWritesShmemSize(void)
+{
+	return sizeof(PgStat_WalWritesStats);
+}
+
+void
+WALWritesShmemInit(void)
+{
+	bool		foundWALWrites;
+
+	WALWriteStats = (PgStat_WalWritesStats *)
+		ShmemInitStruct("WAL WriteStats", WALWritesShmemSize(), &foundWALWrites);
+
+	if (!foundWALWrites)
+	{
+		MemSet(WALWriteStats, 0, sizeof(PgStat_WalWritesStats));
+	}
+}
+
 /*
  * subroutine for pgstat_reset_all
  */
@@ -1336,11 +1368,25 @@ pgstat_reset_shared_counters(const char *target)
 		msg.m_resettarget = RESET_ARCHIVER;
 	else if (strcmp(target, "bgwriter") == 0)
 		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "walwrites") == 0)
+	{
+		/*
+		 * Reset the wal writes statistics of the cluster. These statistics
+		 * are not reset by the stats collector because these are resides in a
+		 * shared memory, so it is not possible for the stats collector to
+		 * reset them. FIXME: This may need a sepearate function entirely to
+		 * reset the stats.
+		 */
+		LWLockAcquire(WALWriteLock, LW_EXCLUSIVE);
+		memset(WALWriteStats, 0, sizeof(PgStat_WalWritesStats));
+		WALWriteStats->stat_reset_timestamp = GetCurrentTimestamp();
+		LWLockRelease(WALWriteLock);
+	}
 	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
-				 errhint("Target must be \"archiver\" or \"bgwriter\".")));
+				 errhint("Target must be \"archiver\" or \"bgwriter\" or \"walwrites\".")));
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
 	pgstat_send(&msg, sizeof(msg));
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 2d1ed143e0..d9e244b5f4 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -150,6 +150,7 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
 		size = add_size(size, BackendRandomShmemSize());
+		size = add_size(size, WALWritesShmemSize());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -218,6 +219,7 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
 	 * Set up xlog, clog, and buffers
 	 */
 	XLOGShmemInit();
+	WALWritesShmemInit();
 	CLOGShmemInit();
 	CommitTsShmemInit();
 	SUBTRANSShmemInit();
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 04cf209b5b..08dd1533d4 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1882,3 +1882,39 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(HeapTupleGetDatum(
 									  heap_form_tuple(tupdesc, values, nulls)));
 }
+
+Datum
+pg_stat_get_walwrites(PG_FUNCTION_ARGS)
+{
+	TupleDesc	tupdesc;
+#define NUM_PG_STAT_WALWRITE_COLS 9
+	Datum		values[NUM_PG_STAT_WALWRITE_COLS];
+	bool		nulls[NUM_PG_STAT_WALWRITE_COLS];
+
+	/* Initialize values and NULL flags arrays */
+	MemSet(values, 0, sizeof(values));
+	MemSet(nulls, 0, sizeof(nulls));
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	LWLockAcquire(WALWriteLock, LW_EXCLUSIVE);
+
+	/* Get statistics about the archiver process */
+	/* Fill values and NULLs */
+	values[0] = Int64GetDatum(WALWriteStats->stats.writes);
+	values[1] = Int64GetDatum(WALWriteStats->stats.walwriter_writes);
+	values[2] = Int64GetDatum(WALWriteStats->stats.backend_writes);
+	values[3] = Int64GetDatum(WALWriteStats->stats.dirty_writes);
+	values[4] = Int64GetDatum(WALWriteStats->stats.backend_dirty_writes);
+	values[5] = Int64GetDatum(WALWriteStats->stats.write_blocks);
+	values[6] = Int64GetDatum(WALWriteStats->stats.walwriter_write_blocks);
+	values[7] = Int64GetDatum(WALWriteStats->stats.backend_write_blocks);
+	values[8] = TimestampTzGetDatum(WALWriteStats->stat_reset_timestamp);
+
+	LWLockRelease(WALWriteLock);
+	/* Returns the record as Datum */
+	PG_RETURN_DATUM(HeapTupleGetDatum(
+									  heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 9680a4b0f7..317be66ab3 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -101,6 +101,7 @@ bool		IsPostmasterEnvironment = false;
 bool		IsUnderPostmaster = false;
 bool		IsBinaryUpgrade = false;
 bool		IsBackgroundWorker = false;
+bool		am_autovacuum_worker = false;
 
 bool		ExitOnAnyError = false;
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index c969375981..a0bb323e1d 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2980,6 +2980,9 @@ DESCR("statistics: number of backend buffer writes that did their own fsync");
 DATA(insert OID = 2859 ( pg_stat_get_buf_alloc			PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 20 "" _null_ _null_ _null_ _null_ _null_ pg_stat_get_buf_alloc _null_ _null_ _null_ ));
 DESCR("statistics: number of buffer allocations");
 
+DATA(insert OID = 3998 (  pg_stat_get_walwrites		PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{20,20,20,20,20,20,20,20,1184}" "{o,o,o,o,o,o,o,o,o}" "{writes,walwriter_writes,backend_writes,dirty_writes,backend_dirty_writes,write_blocks,walwriter_write_blocks,backend_write_blocks,stats_reset}" _null_ _null_ pg_stat_get_walwrites _null_ _null_ _null_ ));
+DESCR("statistics: information about WAL writes activity");
+
 DATA(insert OID = 2978 (  pg_stat_get_function_calls		PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_calls _null_ _null_ _null_ ));
 DESCR("statistics: number of function calls");
 DATA(insert OID = 2979 (  pg_stat_get_function_total_time	PGNSP PGUID 12 1 0 0 0 f f f f t f s r 1 0 701 "26" _null_ _null_ _null_ _null_ _null_ pg_stat_get_function_total_time _null_ _null_ _null_ ));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 59da7a6091..220a23e8e2 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -242,6 +242,8 @@ extern PGDLLIMPORT bool allowSystemTableMods;
 extern PGDLLIMPORT int work_mem;
 extern PGDLLIMPORT int maintenance_work_mem;
 
+extern bool am_autovacuum_worker;
+
 extern int	VacuumCostPageHit;
 extern int	VacuumCostPageMiss;
 extern int	VacuumCostPageDirty;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 089b7c3a10..39f04dbde3 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -422,6 +422,37 @@ typedef struct PgStat_MsgBgWriter
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgBgWriter;
 
+/*
+ * Walwrites statistics counters
+ */
+typedef struct PgStat_WalWritesCounts
+{
+	PgStat_Counter writes;		/* No of writes by background
+								 * processes/workers */
+	PgStat_Counter walwriter_writes;	/* No of writes by walwriter */
+	PgStat_Counter backend_writes;	/* No of writes by backends */
+	PgStat_Counter dirty_writes;	/* No of dirty writes by background
+									 * processes/workers when WAL buffers full */
+	PgStat_Counter backend_dirty_writes;	/* No of dirty writes by backends
+											 * when WAL buffers full */
+	PgStat_Counter write_blocks;	/* Total no of pages written by background
+									 * processes/workers */
+	PgStat_Counter walwriter_write_blocks;	/* Total no of pages written by
+											 * walwriter */
+	PgStat_Counter backend_write_blocks;	/* Total no of pages written by
+											 * backends */
+} PgStat_WalWritesCounts;
+
+/* ----------
+ * PgStat_MsgWalWrites			Sent by the walwriter after collecting all shared stats
+ * ----------
+ */
+typedef struct PgStat_MsgWalWrites
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_WalWritesCounts stats;
+} PgStat_MsgWalWrites;
+
 /* ----------
  * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
  * ----------
@@ -694,6 +725,14 @@ typedef struct PgStat_GlobalStats
 	TimestampTz stat_reset_timestamp;
 } PgStat_GlobalStats;
 
+/*
+ * Walwrites statistics kept in the stats collector
+ */
+typedef struct PgStat_WalWritesStats
+{
+	PgStat_WalWritesCounts stats;
+	TimestampTz stat_reset_timestamp;	/* Last time when the stats reset */
+}			PgStat_WalWritesStats;
 
 /* ----------
  * Backend types
@@ -1125,6 +1164,11 @@ extern char *pgstat_stat_filename;
  */
 extern PgStat_MsgBgWriter BgWriterStats;
 
+/*
+ * Wal writes statistics updated in XLogWrite function
+ */
+extern PgStat_WalWritesStats * WALWriteStats;
+
 /*
  * Updated by pgstat_count_buffer_*_time macros
  */
@@ -1143,6 +1187,9 @@ extern int	pgstat_start(void);
 extern void pgstat_reset_all(void);
 extern void allow_immediate_pgstat_restart(void);
 
+extern Size WALWritesShmemSize(void);
+extern void WALWritesShmemInit(void);
+
 #ifdef EXEC_BACKEND
 extern void PgstatCollectorMain(int argc, char *argv[]) pg_attribute_noreturn();
 #endif
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index f1c1b44d6f..6a84e3f980 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1973,6 +1973,16 @@ pg_stat_wal_receiver| SELECT s.pid,
     s.conninfo
    FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, received_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, conninfo)
   WHERE (s.pid IS NOT NULL);
+pg_stat_walwrites| SELECT a.writes,
+    a.walwriter_writes,
+    a.backend_writes,
+    a.dirty_writes,
+    a.backend_dirty_writes,
+    a.write_blocks,
+    a.walwriter_write_blocks,
+    a.backend_write_blocks,
+    a.stats_reset
+   FROM pg_stat_get_walwrites() a(writes, walwriter_writes, backend_writes, dirty_writes, backend_dirty_writes, write_blocks, walwriter_write_blocks, backend_write_blocks, stats_reset);
 pg_stat_xact_all_tables| SELECT c.oid AS relid,
     n.nspname AS schemaname,
     c.relname,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 2b738aae7c..89619bebaa 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -67,6 +67,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
  t
 (1 row)
 
+-- There will surely and maximum one record
+select count(*) = 1 as ok from pg_stat_walwrites;
+ ok 
+----
+ t
+(1 row)
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
diff --git a/src/test/regress/sql/sysviews.sql b/src/test/regress/sql/sysviews.sql
index 28e412b735..21f49c9a3b 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -32,6 +32,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
 -- See also prepared_xacts.sql
 select count(*) >= 0 as ok from pg_prepared_xacts;
 
+-- There will surely and maximum one record
+select count(*) = 1 as ok from pg_stat_walwrites;
+
 -- This is to record the prevailing planner enable_foo settings during
 -- a regression test run.
 select name, setting from pg_settings where name like 'enable%';
-- 
2.15.0.windows.1