On 2020-10-01 11:33, Amit Kapila wrote:
On Thu, Oct 1, 2020 at 6:53 AM Kyotaro Horiguchi
<horikyota....@gmail.com> wrote:
At Thu, 1 Oct 2020 09:05:19 +0900, Fujii Masao
<masao.fu...@oss.nttdata.com> wrote in
>
>
> On 2020/09/30 20:21, Amit Kapila wrote:
> > On Tue, Sep 29, 2020 at 9:23 PM Fujii Masao
> > <masao.fu...@oss.nttdata.com> wrote:
> >>
> >> On 2020/09/29 11:51, Masahiro Ikeda wrote:
> >>> On 2020-09-29 11:43, Amit Kapila wrote:
> >>>> On Tue, Sep 29, 2020 at 7:39 AM Masahiro Ikeda
> >>>> <ikeda...@oss.nttdata.com> wrote:
> >>> Thanks for your suggestion.
> >>> I understood that the point is that WAL-related stats have just one
> >>> counter now.
> >>>
> >>> Since we may add some WAL-related stats like pgWalUsage.(bytes,
> >>> records, fpi),
> >>> I think that the current approach is good.
> >>
> >> +1
> >>
> > Okay, it makes sense to keep it in the current form if we have a plan
> > to extend this view with additional stats. However, why don't we
> > expose it with a function similar to pg_stat_get_archiver() instead of
> > providing individual functions like pg_stat_get_wal_buffers_full() and
> > pg_stat_get_wal_stat_reset_time?
>
> We can adopt either of those approaches for pg_stat_wal. I think that
> the former is a bit more flexible because we can collect only one of
> WAL information even when pg_stat_wal will contain many information
> in the future, by using the function. But you thought there are some
> reasons that the latter is better for pg_stat_wal?
FWIW I prefer to expose it by one SRF function rather than by
subdivided functions. One of the reasons is the less oid consumption
and/or reduction of definitions for intrinsic functions.
Another reason is at least for me subdivided functions are not useful
so much for on-the-fly examination on psql console. I'm often annoyed
by realizing I can't recall the exact name of a function, say,
pg_last_wal_receive_lsn or such but function names cannot be
auto-completed on psql console. "select proname from pg_proc where
proname like.. " is one of my friends:p On the other hand "select *
from pg_stat_wal" requires no detailed memory.
However subdivided functions might be useful if I wanted use just one
number of wal-stats in a function, I think it is not a major usage and
we can use a SQL query on the view instead.
Another reason that I mildly want to object to subdivided functions is
I was annoyed that a stats view makes many individual calls to
functions that internally share the same statistics entry. That
behavior required me to provide an entry-caching feature to my
shared-memory statistics patch.
All these are good reasons to expose it via one function and I think
that is why most of our existing views also use one function approach.
Thanks for your comments.
I didn't notice there are the above disadvantages to provide individual
functions.
I changed the latest patch to expose it via one function.
Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 4e0193a967..495018009a 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -424,6 +424,14 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
</entry>
</row>
+ <row>
+ <entry><structname>pg_stat_wal</structname><indexterm><primary>pg_stat_wal</primary></indexterm></entry>
+ <entry>One row only, showing statistics about WAL activity. See
+ <link linkend="monitoring-pg-stat-wal-view">
+ <structname>pg_stat_wal</structname></link> 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
@@ -3280,6 +3288,56 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</sect2>
+ <sect2 id="monitoring-pg-stat-wal-view">
+ <title><structname>pg_stat_wal</structname></title>
+
+ <indexterm>
+ <primary>pg_stat_wal</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_stat_wal</structname> view will always have a
+ single row, containing data about WAL activity of the cluster.
+ </para>
+
+ <table id="pg-stat-wal-view" xreflabel="pg_stat_wal">
+ <title><structname>pg_stat_wal</structname> View</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <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
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>stats_reset</structfield> <type>timestamp with time zone</type>
+ </para>
+ <para>
+ Time at which these statistics were last reset
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+</sect2>
+
<sect2 id="monitoring-pg-stat-database-view">
<title><structname>pg_stat_database</structname></title>
@@ -4668,8 +4726,9 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
argument. The argument can be <literal>bgwriter</literal> to reset
all the counters shown in
the <structname>pg_stat_bgwriter</structname>
- view, or <literal>archiver</literal> to reset all the counters shown in
- the <structname>pg_stat_archiver</structname> view.
+ view, <literal>archiver</literal> to reset all the counters shown in
+ the <structname>pg_stat_archiver</structname> view or <literal>wal</literal>
+ to reset all the counters shown in the <structname>pg_stat_wal</structname> view.
</para>
<para>
This function is restricted to superusers by default, but other users
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 79a77ebbfe..64403690da 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -2195,6 +2195,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic)
WriteRqst.Flush = 0;
XLogWrite(WriteRqst, false);
LWLockRelease(WALWriteLock);
+ WalStats.m_wal_buffers_full++;
TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
}
/* Re-acquire WALBufMappingLock and retry */
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index ed4f3f142d..923c2e2be1 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -979,6 +979,12 @@ 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_wal AS
+ SELECT
+ w.wal_buffers_full,
+ w.stats_reset
+ FROM pg_stat_get_wal() w;
+
CREATE VIEW pg_stat_progress_analyze AS
SELECT
S.pid AS pid, S.datid AS datid, D.datname AS datname,
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index 3e7dcd4f76..429c8010ef 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -504,6 +504,9 @@ CheckpointerMain(void)
*/
pgstat_send_bgwriter();
+ /* Send WAL statistics to the stats collector. */
+ pgstat_send_wal();
+
/*
* If any checkpoint flags have been set, redo the loop to handle the
* checkpoint without sleeping.
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index e6be2b7836..9d8a435304 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -135,11 +135,12 @@ char *pgstat_stat_filename = NULL;
char *pgstat_stat_tmpname = NULL;
/*
- * BgWriter global statistics counters (unused in other processes).
- * Stored directly in a stats message structure so it can be sent
- * without needing to copy things around. We assume this inits to zeroes.
+ * BgWriter and WAL global statistics counters.
+ * Stored directly in a stats message structure so they can be sent
+ * without needing to copy things around. We assume these init to zeroes.
*/
PgStat_MsgBgWriter BgWriterStats;
+PgStat_MsgWal WalStats;
/*
* List of SLRU names that we keep stats for. There is no central registry of
@@ -281,6 +282,7 @@ static int localNumBackends = 0;
*/
static PgStat_ArchiverStats archiverStats;
static PgStat_GlobalStats globalStats;
+static PgStat_WalStats walStats;
static PgStat_SLRUStats slruStats[SLRU_NUM_ELEMENTS];
/*
@@ -353,6 +355,7 @@ static void pgstat_recv_vacuum(PgStat_MsgVacuum *msg, int len);
static void pgstat_recv_analyze(PgStat_MsgAnalyze *msg, int len);
static void pgstat_recv_archiver(PgStat_MsgArchiver *msg, int len);
static void pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len);
+static void pgstat_recv_wal(PgStat_MsgWal *msg, int len);
static void pgstat_recv_slru(PgStat_MsgSLRU *msg, int len);
static void pgstat_recv_funcstat(PgStat_MsgFuncstat *msg, int len);
static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len);
@@ -938,6 +941,9 @@ pgstat_report_stat(bool force)
/* Now, send function statistics */
pgstat_send_funcstats();
+ /* Send WAL statistics */
+ pgstat_send_wal();
+
/* Finally send SLRU statistics */
pgstat_send_slru();
}
@@ -1370,11 +1376,13 @@ 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, "wal") == 0)
+ msg.m_resettarget = RESET_WAL;
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\", \"bgwriter\" or \"wal\".")));
pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER);
pgstat_send(&msg, sizeof(msg));
@@ -2674,6 +2682,21 @@ pgstat_fetch_global(void)
return &globalStats;
}
+/*
+ * ---------
+ * pgstat_fetch_stat_wal() -
+ *
+ * Support function for the SQL-callable pgstat* functions. Returns
+ * a pointer to the WAL statistics struct.
+ * ---------
+ */
+PgStat_WalStats *
+pgstat_fetch_stat_wal(void)
+{
+ backend_read_statsfile();
+
+ return &walStats;
+}
/*
* ---------
@@ -4419,6 +4442,38 @@ pgstat_send_bgwriter(void)
MemSet(&BgWriterStats, 0, sizeof(BgWriterStats));
}
+/* ----------
+ * pgstat_send_wal() -
+ *
+ * Send WAL statistics to the collector
+ * ----------
+ */
+void
+pgstat_send_wal(void)
+{
+ /* We assume this initializes to zeroes */
+ static const PgStat_MsgWal 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(&WalStats, &all_zeroes, sizeof(PgStat_MsgWal)) == 0)
+ return;
+
+ /*
+ * Prepare and send the message
+ */
+ pgstat_setheader(&WalStats.m_hdr, PGSTAT_MTYPE_WAL);
+ pgstat_send(&WalStats, sizeof(WalStats));
+
+ /*
+ * Clear out the statistics buffer, so it can be re-used.
+ */
+ MemSet(&WalStats, 0, sizeof(WalStats));
+}
+
/* ----------
* pgstat_send_slru() -
*
@@ -4658,6 +4713,10 @@ PgstatCollectorMain(int argc, char *argv[])
pgstat_recv_bgwriter(&msg.msg_bgwriter, len);
break;
+ case PGSTAT_MTYPE_WAL:
+ pgstat_recv_wal(&msg.msg_wal, len);
+ break;
+
case PGSTAT_MTYPE_SLRU:
pgstat_recv_slru(&msg.msg_slru, len);
break;
@@ -4927,6 +4986,12 @@ 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 stats struct
+ */
+ rc = fwrite(&walStats, sizeof(walStats), 1, fpout);
+ (void) rc; /* we'll check for error with ferror */
+
/*
* Write SLRU stats struct
*/
@@ -5186,11 +5251,12 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
/*
- * Clear out global and archiver statistics so they start from zero in
+ * Clear out global, archiver, WAL and SLRU statistics so they start from zero in
* case we can't load an existing statsfile.
*/
memset(&globalStats, 0, sizeof(globalStats));
memset(&archiverStats, 0, sizeof(archiverStats));
+ memset(&walStats, 0, sizeof(walStats));
memset(&slruStats, 0, sizeof(slruStats));
/*
@@ -5199,6 +5265,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
*/
globalStats.stat_reset_timestamp = GetCurrentTimestamp();
archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
+ walStats.stat_reset_timestamp = globalStats.stat_reset_timestamp;
/*
* Set the same reset timestamp for all SLRU items too.
@@ -5268,6 +5335,17 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep)
goto done;
}
+ /*
+ * Read WAL stats struct
+ */
+ if (fread(&walStats, 1, sizeof(walStats), fpin) != sizeof(walStats))
+ {
+ ereport(pgStatRunningInCollector ? LOG : WARNING,
+ (errmsg("corrupted statistics file \"%s\"", statfile)));
+ memset(&walStats, 0, sizeof(walStats));
+ goto done;
+ }
+
/*
* Read SLRU stats struct
*/
@@ -5578,6 +5656,7 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
PgStat_StatDBEntry dbentry;
PgStat_GlobalStats myGlobalStats;
PgStat_ArchiverStats myArchiverStats;
+ PgStat_WalStats myWalStats;
PgStat_SLRUStats mySLRUStats[SLRU_NUM_ELEMENTS];
FILE *fpin;
int32 format_id;
@@ -5633,6 +5712,17 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent,
return false;
}
+ /*
+ * Read WAL stats struct
+ */
+ if (fread(&myWalStats, 1, sizeof(myWalStats), fpin) != sizeof(myWalStats))
+ {
+ ereport(pgStatRunningInCollector ? LOG : WARNING,
+ (errmsg("corrupted statistics file \"%s\"", statfile)));
+ FreeFile(fpin);
+ return false;
+ }
+
/*
* Read SLRU stats struct
*/
@@ -6213,6 +6303,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
memset(&archiverStats, 0, sizeof(archiverStats));
archiverStats.stat_reset_timestamp = GetCurrentTimestamp();
}
+ else if (msg->m_resettarget == RESET_WAL)
+ {
+ /* Reset the WAL statistics for the cluster. */
+ memset(&walStats, 0, sizeof(walStats));
+ walStats.stat_reset_timestamp = GetCurrentTimestamp();
+ }
/*
* Presumably the sender of this message validated the target, don't
@@ -6427,6 +6523,18 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
globalStats.buf_alloc += msg->m_buf_alloc;
}
+/* ----------
+ * pgstat_recv_wal() -
+ *
+ * Process a WAL message.
+ * ----------
+ */
+static void
+pgstat_recv_wal(PgStat_MsgWal *msg, int len)
+{
+ walStats.wal_buffers_full += msg->m_wal_buffers_full;
+}
+
/* ----------
* pgstat_recv_slru() -
*
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 95738a4e34..24e191ea30 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1697,6 +1697,42 @@ pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
PG_RETURN_INT64(pgstat_fetch_global()->buf_alloc);
}
+/*
+ * Returns statistics of WAL activity
+ */
+Datum
+pg_stat_get_wal(PG_FUNCTION_ARGS)
+{
+#define PG_STAT_GET_WAL_COLS 2
+ TupleDesc tupdesc;
+ Datum values[PG_STAT_GET_WAL_COLS];
+ bool nulls[PG_STAT_GET_WAL_COLS];
+ PgStat_WalStats *wal_stats;
+
+ /* Initialise values and NULL flags arrays */
+ MemSet(values, 0, sizeof(values));
+ MemSet(nulls, 0, sizeof(nulls));
+
+ /* Initialise attributes information in the tuple descriptor */
+ tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_WAL_COLS);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "wal_buffers_full",
+ INT8OID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 2, "stats_reset",
+ TIMESTAMPTZOID, -1, 0);
+
+ BlessTupleDesc(tupdesc);
+
+ /* Get statistics about WAL activity */
+ 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);
+
+ /* Returns the record as Datum */
+ PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
+}
+
/*
* Returns statistics of SLRU caches.
*/
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index f48f5fb4d9..d6f3e2d286 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5481,6 +5481,14 @@
proname => 'pg_stat_get_buf_alloc', provolatile => 's', proparallel => 'r',
prorettype => 'int8', proargtypes => '', prosrc => 'pg_stat_get_buf_alloc' },
+{ 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}',
+ prosrc => 'pg_stat_get_wal' },
+
{ oid => '2306', descr => 'statistics: information about SLRU caches',
proname => 'pg_stat_get_slru', prorows => '100', proisstrict => 'f',
proretset => 't', provolatile => 's', proparallel => 'r',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0dfbac46b4..343eef507e 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -61,6 +61,7 @@ typedef enum StatMsgType
PGSTAT_MTYPE_ANALYZE,
PGSTAT_MTYPE_ARCHIVER,
PGSTAT_MTYPE_BGWRITER,
+ PGSTAT_MTYPE_WAL,
PGSTAT_MTYPE_SLRU,
PGSTAT_MTYPE_FUNCSTAT,
PGSTAT_MTYPE_FUNCPURGE,
@@ -122,7 +123,8 @@ typedef struct PgStat_TableCounts
typedef enum PgStat_Shared_Reset_Target
{
RESET_ARCHIVER,
- RESET_BGWRITER
+ RESET_BGWRITER,
+ RESET_WAL
} PgStat_Shared_Reset_Target;
/* Possible object types for resetting single counters */
@@ -436,6 +438,16 @@ typedef struct PgStat_MsgBgWriter
PgStat_Counter m_checkpoint_sync_time;
} PgStat_MsgBgWriter;
+/* ----------
+ * PgStat_MsgWal Sent by backends and background processes to update WAL statistics.
+ * ----------
+ */
+typedef struct PgStat_MsgWal
+{
+ PgStat_MsgHdr m_hdr;
+ PgStat_Counter m_wal_buffers_full;
+} PgStat_MsgWal;
+
/* ----------
* PgStat_MsgSLRU Sent by a backend to update SLRU statistics.
* ----------
@@ -596,6 +608,7 @@ typedef union PgStat_Msg
PgStat_MsgAnalyze msg_analyze;
PgStat_MsgArchiver msg_archiver;
PgStat_MsgBgWriter msg_bgwriter;
+ PgStat_MsgWal msg_wal;
PgStat_MsgSLRU msg_slru;
PgStat_MsgFuncstat msg_funcstat;
PgStat_MsgFuncpurge msg_funcpurge;
@@ -614,7 +627,7 @@ typedef union PgStat_Msg
* ------------------------------------------------------------
*/
-#define PGSTAT_FILE_FORMAT_ID 0x01A5BC9D
+#define PGSTAT_FILE_FORMAT_ID 0x01A5BC9E
/* ----------
* PgStat_StatDBEntry The collector's data per database
@@ -745,6 +758,15 @@ typedef struct PgStat_GlobalStats
TimestampTz stat_reset_timestamp;
} PgStat_GlobalStats;
+/*
+ * WAL statistics kept in the stats collector
+ */
+typedef struct PgStat_WalStats
+{
+ PgStat_Counter wal_buffers_full;
+ TimestampTz stat_reset_timestamp;
+} PgStat_WalStats;
+
/*
* SLRU statistics kept in the stats collector
*/
@@ -1265,6 +1287,11 @@ extern char *pgstat_stat_filename;
*/
extern PgStat_MsgBgWriter BgWriterStats;
+/*
+ * WAL statistics counter is updated by backends and background processes
+ */
+extern PgStat_MsgWal WalStats;
+
/*
* Updated by pgstat_count_buffer_*_time macros
*/
@@ -1464,6 +1491,7 @@ 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_wal(void);
/* ----------
* Support functions for the SQL-callable functions to
@@ -1478,6 +1506,7 @@ 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_WalStats *pgstat_fetch_stat_wal(void);
extern PgStat_SLRUStats *pgstat_fetch_slru(void);
extern void pgstat_count_slru_page_zeroed(int slru_idx);
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 2a18dc423e..af4192f9a8 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2129,6 +2129,9 @@ 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,
+ w.stats_reset
+ FROM pg_stat_get_wal() w(wal_buffers_full, stats_reset);
pg_stat_wal_receiver| SELECT s.pid,
s.status,
s.receive_start_lsn,
diff --git a/src/test/regress/expected/sysviews.out b/src/test/regress/expected/sysviews.out
index 1cffc3349d..81bdacf59d 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -76,6 +76,13 @@ select count(*) >= 0 as ok from pg_prepared_xacts;
t
(1 row)
+-- There must be only one record
+select count(*) = 1 as ok from pg_stat_wal;
+ 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 ac4a0e1cbb..b9b875bc6a 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -37,6 +37,9 @@ select count(*) = 0 as ok from pg_prepared_statements;
-- See also prepared_xacts.sql
select count(*) >= 0 as ok from pg_prepared_xacts;
+-- There must be only one record
+select count(*) = 1 as ok from pg_stat_wal;
+
-- 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%';
