diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index d973e1149a..9ea5c9b2e2 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -424,6 +424,13 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser + + pg_stat_walwriterpg_stat_walwriter + One row only, showing statistics about the WAL writing activity. See + for details. + + + pg_stat_databasepg_stat_database One row per database, showing database-wide statistics. See @@ -3264,6 +3271,56 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i + + <structname>pg_stat_walwriter</structname> + + + pg_stat_walwriter + + + + The pg_stat_walwriter view will always have a + single row, containing data about the WAL writing activity of the cluster. + + + + <structname>pg_stat_walwriter</structname> View + + + + + Column Type + + + Description + + + + + + + + dirty_writes bigint + + + Number of dirty WAL writes when the are full + + + + + + stats_reset timestamp with time zone + + + Time at which these statistics were last reset + + + + +
+ + + <structname>pg_stat_database</structname> @@ -4652,8 +4709,9 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i argument. The argument can be bgwriter to reset all the counters shown in the pg_stat_bgwriter - view, or archiver to reset all the counters shown in - the pg_stat_archiver view. + view, archiver to reset all the counters shown in + the pg_stat_archiver view ,or walwriter + to reset all the counters shown in the pg_stat_walwriter view. 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 09c01ed4ae..47b148b3b5 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -2193,6 +2193,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic) WriteRqst.Write = OldPageRqstPtr; WriteRqst.Flush = 0; XLogWrite(WriteRqst, false); + WalWriterStats.m_xlog_dirty_writes++; LWLockRelease(WALWriteLock); TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE(); } diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index a2d61302f9..6b43ad61be 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -1000,6 +1000,11 @@ CREATE VIEW pg_stat_progress_analyze AS FROM pg_stat_get_progress_info('ANALYZE') AS S LEFT JOIN pg_database D ON S.datid = D.oid; +CREATE VIEW pg_stat_walwriter AS + SELECT + pg_stat_get_xlog_dirty_writes() AS dirty_writes, + pg_stat_get_walwriter_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/pgstat.c b/src/backend/postmaster/pgstat.c index 8116b23614..154cdc5ddb 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -141,6 +141,14 @@ char *pgstat_stat_tmpname = NULL; */ PgStat_MsgBgWriter BgWriterStats; +/* + * WalWriter global statistics counter. + * This counter is incremented by each XLogWrite call, + * both in the wal writer process and each backend. + * And then, sent to the stat collector process. + */ +PgStat_MsgWalWriter WalWriterStats; + /* * List of SLRU names that we keep stats for. There is no central registry of * SLRUs, so we use this fixed list instead. The "other" entry is used for @@ -281,6 +289,7 @@ static int localNumBackends = 0; */ static PgStat_ArchiverStats archiverStats; static PgStat_GlobalStats globalStats; +static PgStat_WalwriterStats walwriterStats; static PgStat_SLRUStats slruStats[SLRU_NUM_ELEMENTS]; /* @@ -353,6 +362,7 @@ 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_walwriter(PgStat_MsgWalWriter *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 +948,9 @@ pgstat_report_stat(bool force) /* Now, send function statistics */ pgstat_send_funcstats(); + /* Now, send wal writer statistics */ + pgstat_send_walwriter(); + /* Finally send SLRU statistics */ pgstat_send_slru(); } @@ -1370,11 +1383,13 @@ 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, "walwriter") == 0) + msg.m_resettarget = RESET_WALWRITER; 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 \"walwriter\"."))); pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETSHAREDCOUNTER); pgstat_send(&msg, sizeof(msg)); @@ -2674,6 +2689,21 @@ pgstat_fetch_global(void) return &globalStats; } +/* + * --------- + * pgstat_fetch_stat_walwriter() - + * + * Support function for the SQL-callable pgstat* functions. Returns + * a pointer to the walwriter statistics struct. + * --------- + */ +PgStat_WalwriterStats * +pgstat_fetch_stat_walwriter(void) +{ + backend_read_statsfile(); + + return &walwriterStats; +} /* * --------- @@ -4407,6 +4437,38 @@ pgstat_send_bgwriter(void) MemSet(&BgWriterStats, 0, sizeof(BgWriterStats)); } +/* ---------- + * pgstat_send_walwriter() - + * + * Send walwriter statistics to the collector + * ---------- + */ +void +pgstat_send_walwriter(void) +{ + /* We assume this initializes to zeroes */ + static const PgStat_MsgWalWriter 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(&WalWriterStats, &all_zeroes, sizeof(PgStat_MsgWalWriter)) == 0) + return; + + /* + * Prepare and send the message + */ + pgstat_setheader(&WalWriterStats.m_hdr, PGSTAT_MTYPE_WALWRITER); + pgstat_send(&WalWriterStats, sizeof(WalWriterStats)); + + /* + * Clear out the statistics buffer, so it can be re-used. + */ + MemSet(&WalWriterStats, 0, sizeof(WalWriterStats)); +} + /* ---------- * pgstat_send_slru() - * @@ -4646,6 +4708,10 @@ PgstatCollectorMain(int argc, char *argv[]) pgstat_recv_bgwriter(&msg.msg_bgwriter, len); break; + case PGSTAT_MTYPE_WALWRITER: + pgstat_recv_walwriter(&msg.msg_walwriter, len); + break; + case PGSTAT_MTYPE_SLRU: pgstat_recv_slru(&msg.msg_slru, len); break; @@ -4915,6 +4981,12 @@ pgstat_write_statsfiles(bool permanent, bool allDbs) rc = fwrite(&archiverStats, sizeof(archiverStats), 1, fpout); (void) rc; /* we'll check for error with ferror */ + /* + * Write archiver stats struct + */ + rc = fwrite(&walwriterStats, sizeof(walwriterStats), 1, fpout); + (void) rc; /* we'll check for error with ferror */ + /* * Write SLRU stats struct */ @@ -5179,6 +5251,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep) */ memset(&globalStats, 0, sizeof(globalStats)); memset(&archiverStats, 0, sizeof(archiverStats)); + memset(&walwriterStats, 0, sizeof(walwriterStats)); memset(&slruStats, 0, sizeof(slruStats)); /* @@ -5187,6 +5260,7 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep) */ globalStats.stat_reset_timestamp = GetCurrentTimestamp(); archiverStats.stat_reset_timestamp = globalStats.stat_reset_timestamp; + walwriterStats.stat_reset_timestamp = globalStats.stat_reset_timestamp; /* * Set the same reset timestamp for all SLRU items too. @@ -5256,6 +5330,17 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep) goto done; } + /* + * Read walwriter stats struct + */ + if (fread(&walwriterStats, 1, sizeof(walwriterStats), fpin) != sizeof(walwriterStats)) + { + ereport(pgStatRunningInCollector ? LOG : WARNING, + (errmsg("corrupted statistics file \"%s\"", statfile))); + memset(&walwriterStats, 0, sizeof(walwriterStats)); + goto done; + } + /* * Read SLRU stats struct */ @@ -5266,7 +5351,6 @@ pgstat_read_statsfiles(Oid onlydb, bool permanent, bool deep) memset(&slruStats, 0, sizeof(slruStats)); goto done; } - /* * We found an existing collector stats file. Read it and put all the * hashtable entries into place. @@ -5620,6 +5704,17 @@ pgstat_read_db_statsfile_timestamp(Oid databaseid, bool permanent, return false; } + /* + * Read walwriter stats struct + */ + if (fread(&walwriterStats, 1, sizeof(walwriterStats), fpin) != sizeof(walwriterStats)) + { + ereport(pgStatRunningInCollector ? LOG : WARNING, + (errmsg("corrupted statistics file \"%s\"", statfile))); + FreeFile(fpin); + return false; + } + /* * Read SLRU stats struct */ @@ -6196,6 +6291,12 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len) memset(&archiverStats, 0, sizeof(archiverStats)); archiverStats.stat_reset_timestamp = GetCurrentTimestamp(); } + else if (msg->m_resettarget == RESET_WALWRITER) + { + /* Reset the walwriter statistics for the cluster. */ + memset(&walwriterStats, 0, sizeof(walwriterStats)); + walwriterStats.stat_reset_timestamp = GetCurrentTimestamp(); + } /* * Presumably the sender of this message validated the target, don't @@ -6410,6 +6511,18 @@ pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len) globalStats.buf_alloc += msg->m_buf_alloc; } +/* ---------- + * pgstat_recv_walwriter() - + * + * Process a WALWRITER message. + * ---------- + */ +static void +pgstat_recv_walwriter(PgStat_MsgWalWriter *msg, int len) +{ + walwriterStats.xlog_dirty_writes += msg->m_xlog_dirty_writes; +} + /* ---------- * pgstat_recv_slru() - * diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c index 45a2757969..309cce2c64 100644 --- a/src/backend/postmaster/walwriter.c +++ b/src/backend/postmaster/walwriter.c @@ -243,6 +243,8 @@ WalWriterMain(void) else if (left_till_hibernate > 0) left_till_hibernate--; + pgstat_send_walwriter(); + /* * 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 95738a4e34..672ed9c8ca 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -1697,6 +1697,18 @@ pg_stat_get_buf_alloc(PG_FUNCTION_ARGS) PG_RETURN_INT64(pgstat_fetch_global()->buf_alloc); } +Datum +pg_stat_get_xlog_dirty_writes(PG_FUNCTION_ARGS) +{ + PG_RETURN_INT64(pgstat_fetch_stat_walwriter()->xlog_dirty_writes); +} + +Datum +pg_stat_get_walwriter_stat_reset_time(PG_FUNCTION_ARGS) +{ + PG_RETURN_TIMESTAMPTZ(pgstat_fetch_stat_walwriter()->stat_reset_timestamp); +} + /* * Returns statistics of SLRU caches. */ diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 1dd325e0e6..131709ebfe 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5476,6 +5476,14 @@ proname => 'pg_stat_get_buf_alloc', provolatile => 's', proparallel => 'r', prorettype => 'int8', proargtypes => '', prosrc => 'pg_stat_get_buf_alloc' }, +{ oid => '8000', descr => 'statistics: number of dirty WAL writes', + proname => 'pg_stat_get_xlog_dirty_writes', provolatile => 's', proparallel => 'r', + prorettype => 'int8', proargtypes => '', prosrc => 'pg_stat_get_xlog_dirty_writes' }, +{ oid => '8001', descr => 'statistics: last reset for the walwriter', + proname => 'pg_stat_get_walwriter_stat_reset_time', provolatile => 's', + proparallel => 'r', prorettype => 'timestamptz', proargtypes => '', + prosrc => 'pg_stat_get_walwriter_stat_reset_time' }, + { 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 807a9c1edf..873da60e70 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_WALWRITER, 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_WALWRITER } PgStat_Shared_Reset_Target; /* Possible object types for resetting single counters */ @@ -436,6 +438,17 @@ typedef struct PgStat_MsgBgWriter PgStat_Counter m_checkpoint_sync_time; } PgStat_MsgBgWriter; +/* ---------- + * PgStat_MsgWalWriter Sent by the walwriter to update statistics. + * ---------- + */ +typedef struct PgStat_MsgWalWriter +{ + PgStat_MsgHdr m_hdr; + + PgStat_Counter m_xlog_dirty_writes; /* number of WAL write caused by full of WAL buffers */ +} PgStat_MsgWalWriter; + /* ---------- * PgStat_MsgSLRU Sent by a backend to update SLRU statistics. * ---------- @@ -596,6 +609,7 @@ typedef union PgStat_Msg PgStat_MsgAnalyze msg_analyze; PgStat_MsgArchiver msg_archiver; PgStat_MsgBgWriter msg_bgwriter; + PgStat_MsgWalWriter msg_walwriter; PgStat_MsgSLRU msg_slru; PgStat_MsgFuncstat msg_funcstat; PgStat_MsgFuncpurge msg_funcpurge; @@ -745,6 +759,20 @@ typedef struct PgStat_GlobalStats TimestampTz stat_reset_timestamp; } PgStat_GlobalStats; +/* + * Walwriter statistics kept in the stats collector + */ +typedef struct PgStat_WalwriterStats +{ + PgStat_Counter xlog_dirty_writes; /* number of WAL write caused by full of WAL buffers */ + TimestampTz stat_reset_timestamp; /* last time when the stats reset */ +} PgStat_WalwriterStats; + +/* ---------- + * Backend types + * ---------- + */ + /* * SLRU statistics kept in the stats collector */ @@ -1261,6 +1289,11 @@ extern char *pgstat_stat_filename; */ extern PgStat_MsgBgWriter BgWriterStats; +/* + * WAL writes statistics counter is updated in XLogWrite function + */ +extern PgStat_MsgWalWriter WalWriterStats; + /* * Updated by pgstat_count_buffer_*_time macros */ @@ -1460,6 +1493,7 @@ 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_walwriter(void); /* ---------- * Support functions for the SQL-callable functions to @@ -1474,6 +1508,7 @@ 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_WalwriterStats *pgstat_fetch_stat_walwriter(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..4c7e6c5316 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -2146,6 +2146,8 @@ pg_stat_wal_receiver| SELECT s.pid, s.conninfo FROM pg_stat_get_wal_receiver() s(pid, status, receive_start_lsn, receive_start_tli, written_lsn, flushed_lsn, received_tli, last_msg_send_time, last_msg_receipt_time, latest_end_lsn, latest_end_time, slot_name, sender_host, sender_port, conninfo) WHERE (s.pid IS NOT NULL); +pg_stat_walwriter| SELECT pg_stat_get_xlog_dirty_writes() AS dirty_writes, + pg_stat_get_walwriter_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 1cffc3349d..1e828ccfde 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 will surely and maximum one record +select count(*) = 1 as ok from pg_stat_walwriter; + 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..ab1a416c13 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 will surely and maximum one record +select count(*) = 1 as ok from pg_stat_walwriter; + -- 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%';