0002_add_statistics_to_pg_stat_wal_view.patch

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 6656676..ee70b7b 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -3406,12 +3406,115 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
     </thead>
 
     <tbody>
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_records</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL records generated
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_fpi</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL full page images generated
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_bytes</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total amount of WAL bytes generated
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>wal_buffers_full</structfield> <type>bigint</type>
       </para>
       <para>
-       Number of times WAL data was written to the disk because WAL buffers got full
+       Total number of WAL data written to the disk because WAL buffers got full
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_file</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL file segment created or opened a pre-existing one
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_init_file</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL file segment created
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_write_backend</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL data written to the disk by backends
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_write_walwriter</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL data written to the disk by walwriter
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_write_time</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total amount of time that has been spent in the portion of
+       WAL data was written to disk by backend and walwriter, in milliseconds
+       (if <xref linkend="guc-track-io-timing"/> is enabled, otherwise zero)
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_sync_backend</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL data synced to the disk by backends
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_sync_walwriter</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total number of WAL data synced to the disk by walwriter
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>wal_sync_time</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Total amount of time that has been spent in the portion of
+       WAL data was synced to disk by backend and walwriter, in milliseconds
+       (if <xref linkend="guc-track-io-timing"/> is enabled, otherwise zero)
       </para></entry>
      </row>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 52a67b1..f7316d2 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -1262,6 +1262,10 @@ XLogInsertRecord(XLogRecData *rdata,
 		pgWalUsage.wal_bytes += rechdr->xl_tot_len;
 		pgWalUsage.wal_records++;
 		pgWalUsage.wal_fpi += num_fpi;
+
+		WalStats.m_wal_bytes += rechdr->xl_tot_len;
+		WalStats.m_wal_records++;
+		WalStats.m_wal_fpi += num_fpi;
 	}
 
 	return EndPos;
@@ -2527,6 +2531,8 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			Size		nbytes;
 			Size		nleft;
 			int			written;
+			instr_time	start;
+			instr_time	duration;
 
 			/* OK to write the page(s) */
 			from = XLogCtl->pages + startidx * (Size) XLOG_BLCKSZ;
@@ -2535,9 +2541,28 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible)
 			do
 			{
 				errno = 0;
+				if (track_io_timing)
+					INSTR_TIME_SET_CURRENT(start);
+
 				pgstat_report_wait_start(WAIT_EVENT_WAL_WRITE);
 				written = pg_pwrite(openLogFile, from, nleft, startoffset);
 				pgstat_report_wait_end();
+
+				if (track_io_timing)
+				{
+					INSTR_TIME_SET_CURRENT(duration);
+					INSTR_TIME_SUBTRACT(duration, start);
+					WalStats.m_wal_write_time += INSTR_TIME_GET_MILLISEC(duration);
+				}
+
+				if (AmWalWriterProcess()){
+					WalStats.m_wal_write_walwriter++;
+				}
+				else
+				{
+					WalStats.m_wal_write_backend++;
+				}
+
 				if (written <= 0)
 				{
 					char		xlogfname[MAXFNAMELEN];
@@ -3278,7 +3303,10 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
 						 errmsg("could not open file \"%s\": %m", path)));
 		}
 		else
+		{
+			WalStats.m_wal_file++;
 			return fd;
+		}
 	}
 
 	/*
@@ -3418,6 +3446,8 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
 				 errmsg("could not open file \"%s\": %m", path)));
 
 	elog(DEBUG2, "done creating and filling new WAL file");
+	WalStats.m_wal_init_file++;
+	WalStats.m_wal_file++;
 
 	return fd;
 }
@@ -10427,8 +10457,13 @@ assign_xlog_sync_method(int new_sync_method, void *extra)
 void
 issue_xlog_fsync(int fd, XLogSegNo segno)
 {
+	instr_time	start;
+	instr_time	duration;
 	char	   *msg = NULL;
 
+	if (track_io_timing)
+		INSTR_TIME_SET_CURRENT(start);
+
 	pgstat_report_wait_start(WAIT_EVENT_WAL_SYNC);
 	switch (sync_method)
 	{
@@ -10472,6 +10507,21 @@ issue_xlog_fsync(int fd, XLogSegNo segno)
 	}
 
 	pgstat_report_wait_end();
+
+	if (track_io_timing)
+	{
+		INSTR_TIME_SET_CURRENT(duration);
+		INSTR_TIME_SUBTRACT(duration, start);
+		WalStats.m_wal_sync_time += INSTR_TIME_GET_MICROSEC(duration);
+	}
+
+	if (AmWalWriterProcess()){
+		WalStats.m_wal_sync_walwriter++;
+	}
+	else
+	{
+		WalStats.m_wal_sync_backend++;
+	}
 }
 
 /*
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index c293907..f0acfa8 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -990,7 +990,18 @@ CREATE VIEW pg_stat_bgwriter AS
 
 CREATE VIEW pg_stat_wal AS
     SELECT
+        w.wal_records,
+        w.wal_fpi,
+        w.wal_bytes,
         w.wal_buffers_full,
+        w.wal_file,
+        w.wal_init_file,
+        w.wal_write_backend,
+        w.wal_write_walwriter,
+        w.wal_write_time,
+        w.wal_sync_backend,
+        w.wal_sync_walwriter,
+        w.wal_sync_time,
         w.stats_reset
     FROM pg_stat_get_wal() w;
 
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 822f0eb..f74b431 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -6756,7 +6756,18 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 static void
 pgstat_recv_wal(PgStat_MsgWal *msg, int len)
 {
+	walStats.wal_records += msg->m_wal_records;
+	walStats.wal_fpi += msg->m_wal_fpi;
+	walStats.wal_bytes += msg->m_wal_bytes;
 	walStats.wal_buffers_full += msg->m_wal_buffers_full;
+	walStats.wal_file += msg->m_wal_file;
+	walStats.wal_init_file += msg->m_wal_init_file;
+	walStats.wal_write_backend += msg->m_wal_write_backend;
+	walStats.wal_write_walwriter += msg->m_wal_write_walwriter;
+	walStats.wal_write_time += msg->m_wal_write_time;
+	walStats.wal_sync_backend += msg->m_wal_sync_backend;
+	walStats.wal_sync_walwriter += msg->m_wal_sync_walwriter;
+	walStats.wal_sync_time += msg->m_wal_sync_time;
 }
 
 /* ----------
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index a52832f..ce9f4b7 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -253,6 +253,9 @@ WalWriterMain(void)
 		else if (left_till_hibernate > 0)
 			left_till_hibernate--;
 
+		/* Send WAL statistics */
+		pgstat_send_wal();
+
 		/*
 		 * 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 0d0d2e6..e21f698 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1703,7 +1703,7 @@ pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_wal(PG_FUNCTION_ARGS)
 {
-#define PG_STAT_GET_WAL_COLS	2
+#define PG_STAT_GET_WAL_COLS	13
 	TupleDesc	tupdesc;
 	Datum		values[PG_STAT_GET_WAL_COLS];
 	bool		nulls[PG_STAT_GET_WAL_COLS];
@@ -1715,9 +1715,31 @@ pg_stat_get_wal(PG_FUNCTION_ARGS)
 
 	/* Initialise attributes information in the tuple descriptor */
 	tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_WAL_COLS);
-	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "wal_buffers_full",
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "wal_records",
 					   INT8OID, -1, 0);
-	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "stats_reset",
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "wal_fpi",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "wal_bytes",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "wal_buffers_full",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "wal_file",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "wal_init_file",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 7, "wal_write_backend",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 8, "wal_write_walwriter",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 9, "wal_write_time",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 10, "wal_sync_backend",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 11, "wal_sync_walwriter",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 12, "wal_sync_time",
+					   INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
@@ -1726,8 +1748,19 @@ pg_stat_get_wal(PG_FUNCTION_ARGS)
 	wal_stats = pgstat_fetch_stat_wal();
 
 	/* Fill values and NULLs */
-	values[0] = Int64GetDatum(wal_stats->wal_buffers_full);
-	values[1] = TimestampTzGetDatum(wal_stats->stat_reset_timestamp);
+	values[0] = Int64GetDatum(wal_stats->wal_records);
+	values[1] = Int64GetDatum(wal_stats->wal_fpi);
+	values[2] = Int64GetDatum(wal_stats->wal_bytes);
+	values[3] = Int64GetDatum(wal_stats->wal_buffers_full);
+	values[4] = Int64GetDatum(wal_stats->wal_file);
+	values[5] = Int64GetDatum(wal_stats->wal_init_file);
+	values[6] = Int64GetDatum(wal_stats->wal_write_backend);
+	values[7] = Int64GetDatum(wal_stats->wal_write_walwriter);
+	values[8] = Int64GetDatum(wal_stats->wal_write_time);
+	values[9] = Int64GetDatum(wal_stats->wal_sync_backend);
+	values[10] = Int64GetDatum(wal_stats->wal_sync_walwriter);
+	values[11] = Int64GetDatum(wal_stats->wal_sync_time);
+	values[12] = TimestampTzGetDatum(wal_stats->stat_reset_timestamp);
 
 	/* Returns the record as Datum */
 	PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 22340ba..f8c3ccb 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5492,9 +5492,9 @@
 { oid => '1136', descr => 'statistics: information about WAL activity',
   proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
   proparallel => 'r', prorettype => 'record', proargtypes => '',
-  proallargtypes => '{int8,timestamptz}',
-  proargmodes => '{o,o}',
-  proargnames => '{wal_buffers_full,stats_reset}',
+  proallargtypes => '{int8,int8,int8,int8,int8,int8,int8,int8,int8,int8,int8,int8,timestamptz}',
+  proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{wal_records,wal_fpi,wal_bytes,wal_buffers_full,wal_file,wal_init_file,wal_write_backend,wal_write_walwriter,wal_write_time,wal_sync_backend,wal_sync_walwriter,wal_sync_time,stats_reset}',
   prosrc => 'pg_stat_get_wal' },
 
 { oid => '2306', descr => 'statistics: information about SLRU caches',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index a821ff4..25490ed 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -459,7 +459,18 @@ typedef struct PgStat_MsgBgWriter
 typedef struct PgStat_MsgWal
 {
 	PgStat_MsgHdr m_hdr;
+	PgStat_Counter m_wal_records;
+	PgStat_Counter m_wal_fpi;
+	PgStat_Counter m_wal_bytes;
 	PgStat_Counter m_wal_buffers_full;
+	PgStat_Counter m_wal_file;
+	PgStat_Counter m_wal_init_file;
+	PgStat_Counter m_wal_write_backend;
+	PgStat_Counter m_wal_write_walwriter;
+	PgStat_Counter m_wal_write_time;	/* accumulate times in milliseconds */
+	PgStat_Counter m_wal_sync_backend;
+	PgStat_Counter m_wal_sync_walwriter;
+	PgStat_Counter m_wal_sync_time; /* accumulate times in milliseconds */
 } PgStat_MsgWal;
 
 /* ----------
@@ -795,7 +806,19 @@ typedef struct PgStat_GlobalStats
  */
 typedef struct PgStat_WalStats
 {
+	PgStat_Counter wal_records;
+	PgStat_Counter wal_fpi;
+	PgStat_Counter wal_bytes;
 	PgStat_Counter wal_buffers_full;
+	PgStat_Counter wal_file;
+	PgStat_Counter wal_init_file;
+	PgStat_Counter wal_write_backend;
+	PgStat_Counter wal_write_walwriter;
+	PgStat_Counter wal_write_time;
+	PgStat_Counter wal_sync_backend;
+	PgStat_Counter wal_sync_walwriter;
+	PgStat_Counter wal_sync_time;
+
 	TimestampTz stat_reset_timestamp;
 } PgStat_WalStats;
 
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index cf2a9b4..019fd50 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2135,9 +2135,20 @@ pg_stat_user_tables| SELECT pg_stat_all_tables.relid,
     pg_stat_all_tables.autoanalyze_count
    FROM pg_stat_all_tables
   WHERE ((pg_stat_all_tables.schemaname <> ALL (ARRAY['pg_catalog'::name, 'information_schema'::name])) AND (pg_stat_all_tables.schemaname !~ '^pg_toast'::text));
-pg_stat_wal| SELECT w.wal_buffers_full,
+pg_stat_wal| SELECT w.wal_records,
+    w.wal_fpi,
+    w.wal_bytes,
+    w.wal_buffers_full,
+    w.wal_file,
+    w.wal_init_file,
+    w.wal_write_backend,
+    w.wal_write_walwriter,
+    w.wal_write_time,
+    w.wal_sync_backend,
+    w.wal_sync_walwriter,
+    w.wal_sync_time,
     w.stats_reset
-   FROM pg_stat_get_wal() w(wal_buffers_full, stats_reset);
+   FROM pg_stat_get_wal() w(wal_records, wal_fpi, wal_bytes, wal_buffers_full, wal_file, wal_init_file, wal_write_backend, wal_write_walwriter, wal_write_time, wal_sync_backend, wal_sync_walwriter, wal_sync_time, stats_reset);
 pg_stat_wal_receiver| SELECT s.pid,
     s.status,
     s.receive_start_lsn,