database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-03 15:22:11 +03:00
Code Activity

Add pg_stat_wal statistics view.

Browse Source 
This view shows the statistics about WAL activity. Currently it has only
two columns: wal_buffers_full and stats_reset. wal_buffers_full column
indicates the number of times WAL data was written to the disk because
WAL buffers got full. This information is useful when tuning wal_buffers.
stats_reset column indicates the time at which these statistics were
last reset.

pg_stat_wal view is also the basic infrastructure to expose other
various statistics about WAL activity later.

Bump PGSTAT_FILE_FORMAT_ID due to the change in pgstat format.

Bump catalog version.

Author: Masahiro Ikeda
Reviewed-by: Takayuki Tsunakawa, Kyotaro Horiguchi, Amit Kapila, Fujii Masao
Discussion: https://postgr.es/m/188bd3f2d2233cf97753b5ced02bb050@oss.nttdata.com
This commit is contained in:
Fujii Masao
2020-10-02 10:17:11 +09:00
parent 9d0bd95fa9
commit 8d9a935965
13 changed files with 276 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
src/backend/access/transam/xlog.c
View File

@@ -2196,6 +2196,7 @@ 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 */

6
src/backend/catalog/system_views.sql
View File

@@ -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,

3
src/backend/postmaster/checkpointer.c
View File

@@ -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.

120
src/backend/postmaster/pgstat.c
View File

@@ -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
* case we can't load an existing statsfile.
* 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() -
*

36
src/backend/utils/adt/pgstatfuncs.c
View File

@@ -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.
*/