diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 7dcddf478a..d49e539da3 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 + + pg_stat_walwritespg_stat_walwrites + 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 @@ -3244,6 +3252,48 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i + + <structname>pg_stat_walwrites</structname> + + + pg_stat_walwrites + + + + The pg_stat_walwrites view will always have a + single row, containing data about the WAL writing activity of the cluster. + + + + <structname>pg_stat_walwrites</structname> View + + + + + Column Type + + + Description + + + + + + + + dirty_writes bigint + + + Number of dirty WAL writes that are carried out by background processes and workers + when the are full. + + + + +
+ + + <structname>pg_stat_database</structname> @@ -4632,8 +4682,9 @@ 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 walwrites + to reset all the counters shown in the pg_stat_walwrites 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 756b838e6a..66abd200d1 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); + WALWriteStats->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 8625cbeab6..cfc6a13b6a 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -994,6 +994,9 @@ 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_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/pgstat.c b/src/backend/postmaster/pgstat.c index 15f92b66c6..17feecd1a5 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -167,6 +167,15 @@ static const char *const slru_names[] = { */ static PgStat_MsgSLRU SLRUStats[SLRU_NUM_ELEMENTS]; +/* + * 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 * ---------- @@ -657,6 +666,29 @@ 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 */ @@ -1370,11 +1402,25 @@ 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 96c2aaabbd..a49760ee24 100644 --- a/src/backend/storage/ipc/ipci.c +++ b/src/backend/storage/ipc/ipci.c @@ -149,6 +149,7 @@ CreateSharedMemoryAndSemaphores(void) size = add_size(size, BTreeShmemSize()); size = add_size(size, SyncScanShmemSize()); size = add_size(size, AsyncShmemSize()); + size = add_size(size, WALWritesShmemSize()); #ifdef EXEC_BACKEND size = add_size(size, ShmemBackendArraySize()); #endif @@ -216,6 +217,7 @@ CreateSharedMemoryAndSemaphores(void) * 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 95738a4e34..12d762ef6a 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -2098,3 +2098,38 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS) /* Returns the record as Datum */ PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls))); } + +Datum +pg_stat_get_walwrites(PG_FUNCTION_ARGS) +{ + TupleDesc tupdesc; + TimestampTz result; +#define NUM_PG_STAT_WALWRITE_COLS 2 + 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->dirty_writes); + + result = TimestampTzGetDatum(WALWriteStats->stat_reset_timestamp); + if (result == 0) + nulls[1] = true; + else + values[1] = result; + + LWLockRelease(WALWriteLock); + /* 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 082a11f270..f87bfdcfa9 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5484,6 +5484,14 @@ proargnames => '{name,blks_zeroed,blks_hit,blks_read,blks_written,blks_exists,flushes,truncates,stats_reset}', prosrc => 'pg_stat_get_slru' }, +{ oid => '8000', descr => 'statistics: information about WAL writes activity', + proname => 'pg_stat_get_walwrites', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => '', + proallargtypes => '{int8,timestamptz}', + proargmodes => '{o,o}', + proargnames => '{dirty_writes,stats_reset}', + prosrc => 'pg_stat_get_walwrites' }, + { oid => '2978', descr => 'statistics: number of function calls', proname => 'pg_stat_get_function_calls', provolatile => 's', proparallel => 'r', prorettype => 'int8', proargtypes => 'oid', diff --git a/src/include/pgstat.h b/src/include/pgstat.h index 1387201382..94e4da6fd7 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -745,6 +745,19 @@ typedef struct PgStat_GlobalStats TimestampTz stat_reset_timestamp; } PgStat_GlobalStats; +/* + * Walwrites statistics kept in the stats collector + */ +typedef struct PgStat_WalWritesStats +{ + PgStat_Counter dirty_writes; /* number of WAL write caused by full of WAL buffers */ + TimestampTz stat_reset_timestamp; /* last time when the stats reset */ +} PgStat_WalWritesStats; + +/* ---------- + * Backend types + * ---------- + /* * SLRU statistics kept in the stats collector */ @@ -1260,6 +1273,11 @@ 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 */ @@ -1278,6 +1296,9 @@ 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 601734a6f1..3457cf2904 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -2136,6 +2136,9 @@ 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_walwrites| SELECT a.dirty_writes, + a.stats_reset + FROM pg_stat_get_walwrites() a(dirty_writes, 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 06c4c3e476..3c04c57023 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%';