Fujii, Alexander thanks a lot!
On 17.09.2024 05:47, Fujii Masao wrote:
Regarding the patch:
if (do_restartpoint)
PendingCheckpointerStats.restartpoints_performed++;
+ else
+ PendingCheckpointerStats.num_performed++;
I expected the counter not to be incremented when a checkpoint is skipped,
but in this code, when a checkpoint is skipped, ckpt_performed is set to true,
triggering the counter increment. This seems wrong.
Tried to fix it via returning bool value from the CreateCheckPoint()
similarly to the CreateRestartPoint().
And slightly adjusted the patch so that it could be applied after yours.
With the best wishes,
--
Anton A. Melnikov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
From 97595f65cb12eb2243e1b7391e1bc77bd161f41c Mon Sep 17 00:00:00 2001
From: "Anton A. Melnikov" <a.melni...@postgrespro.ru>
Date: Mon, 16 Sep 2024 16:12:07 +0300
Subject: [PATCH] Introduce num_done counter in the pg_stat_checkpointer view
that reflects number of really performed checkpoints.
---
doc/src/sgml/monitoring.sgml | 11 ++++-
src/backend/access/transam/xlog.c | 6 ++-
src/backend/catalog/system_views.sql | 1 +
src/backend/postmaster/checkpointer.c | 5 ++-
.../utils/activity/pgstat_checkpointer.c | 2 +
src/backend/utils/adt/pgstatfuncs.c | 6 +++
src/include/access/xlog.h | 2 +-
src/include/catalog/pg_proc.dat | 40 +++++++++++--------
src/include/pgstat.h | 1 +
src/test/regress/expected/rules.out | 1 +
10 files changed, 52 insertions(+), 23 deletions(-)
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index a2fda4677d7..19bf0164f1c 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -3063,7 +3063,16 @@ description | Waiting for a newly initialized WAL file to reach durable storage
<structfield>num_requested</structfield> <type>bigint</type>
</para>
<para>
- Number of requested checkpoints that have been performed
+ Number of backend requested checkpoints
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>num_done</structfield> <type>bigint</type>
+ </para>
+ <para>
+ Number of checkpoints that have been performed
</para></entry>
</row>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 853ab06812b..ca1155567dc 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6879,7 +6879,7 @@ update_checkpoint_display(int flags, bool restartpoint, bool reset)
* both the record marking the completion of the checkpoint and the location
* from which WAL replay would begin if needed.
*/
-void
+bool
CreateCheckPoint(int flags)
{
bool shutdown;
@@ -6971,7 +6971,7 @@ CreateCheckPoint(int flags)
END_CRIT_SECTION();
ereport(DEBUG1,
(errmsg_internal("checkpoint skipped because system is idle")));
- return;
+ return false;
}
}
@@ -7353,6 +7353,8 @@ CreateCheckPoint(int flags)
CheckpointStats.ckpt_segs_added,
CheckpointStats.ckpt_segs_removed,
CheckpointStats.ckpt_segs_recycled);
+
+ return true;
}
/*
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 7fd5d256a18..49109dbdc86 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1138,6 +1138,7 @@ CREATE VIEW pg_stat_checkpointer AS
SELECT
pg_stat_get_checkpointer_num_timed() AS num_timed,
pg_stat_get_checkpointer_num_requested() AS num_requested,
+ pg_stat_get_checkpointer_num_performed() AS num_done,
pg_stat_get_checkpointer_restartpoints_timed() AS restartpoints_timed,
pg_stat_get_checkpointer_restartpoints_requested() AS restartpoints_req,
pg_stat_get_checkpointer_restartpoints_performed() AS restartpoints_done,
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index eeb73c85726..ef29cb439b2 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -461,8 +461,7 @@ CheckpointerMain(char *startup_data, size_t startup_data_len)
*/
if (!do_restartpoint)
{
- CreateCheckPoint(flags);
- ckpt_performed = true;
+ ckpt_performed = CreateCheckPoint(flags);
}
else
ckpt_performed = CreateRestartPoint(flags);
@@ -495,6 +494,8 @@ CheckpointerMain(char *startup_data, size_t startup_data_len)
if (do_restartpoint)
PendingCheckpointerStats.restartpoints_performed++;
+ else
+ PendingCheckpointerStats.num_performed++;
}
else
{
diff --git a/src/backend/utils/activity/pgstat_checkpointer.c b/src/backend/utils/activity/pgstat_checkpointer.c
index bbfc9c7e183..4a0a2d1493a 100644
--- a/src/backend/utils/activity/pgstat_checkpointer.c
+++ b/src/backend/utils/activity/pgstat_checkpointer.c
@@ -49,6 +49,7 @@ pgstat_report_checkpointer(void)
#define CHECKPOINTER_ACC(fld) stats_shmem->stats.fld += PendingCheckpointerStats.fld
CHECKPOINTER_ACC(num_timed);
CHECKPOINTER_ACC(num_requested);
+ CHECKPOINTER_ACC(num_performed);
CHECKPOINTER_ACC(restartpoints_timed);
CHECKPOINTER_ACC(restartpoints_requested);
CHECKPOINTER_ACC(restartpoints_performed);
@@ -127,6 +128,7 @@ pgstat_checkpointer_snapshot_cb(void)
#define CHECKPOINTER_COMP(fld) pgStatLocal.snapshot.checkpointer.fld -= reset.fld;
CHECKPOINTER_COMP(num_timed);
CHECKPOINTER_COMP(num_requested);
+ CHECKPOINTER_COMP(num_performed);
CHECKPOINTER_COMP(restartpoints_timed);
CHECKPOINTER_COMP(restartpoints_requested);
CHECKPOINTER_COMP(restartpoints_performed);
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 9c23ac7c8c8..17b0fc02ef0 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1191,6 +1191,12 @@ pg_stat_get_checkpointer_num_requested(PG_FUNCTION_ARGS)
PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->num_requested);
}
+Datum
+pg_stat_get_checkpointer_num_performed(PG_FUNCTION_ARGS)
+{
+ PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->num_performed);
+}
+
Datum
pg_stat_get_checkpointer_restartpoints_timed(PG_FUNCTION_ARGS)
{
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 083810f5b4c..36f6e4e4b4e 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -239,7 +239,7 @@ extern void LocalProcessControlFile(bool reset);
extern WalLevel GetActiveWalLevelOnStandby(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(int code, Datum arg);
-extern void CreateCheckPoint(int flags);
+extern bool CreateCheckPoint(int flags);
extern bool CreateRestartPoint(int flags);
extern WALAvailability GetWALAvailability(XLogRecPtr targetLSN);
extern void XLogPutNextOid(Oid nextOid);
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 43f608d7a0a..83c96140b01 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5807,42 +5807,58 @@
proargmodes => '{o,o,o,o,o,o,o}',
proargnames => '{archived_count,last_archived_wal,last_archived_time,failed_count,last_failed_wal,last_failed_time,stats_reset}',
prosrc => 'pg_stat_get_archiver' },
-{ oid => '2769',
+{ oid => '6347',
descr => 'statistics: number of timed checkpoints started by the checkpointer',
proname => 'pg_stat_get_checkpointer_num_timed', provolatile => 's',
proparallel => 'r', prorettype => 'int8', proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_num_timed' },
-{ oid => '2770',
+{ oid => '6348',
descr => 'statistics: number of backend requested checkpoints started by the checkpointer',
proname => 'pg_stat_get_checkpointer_num_requested', provolatile => 's',
proparallel => 'r', prorettype => 'int8', proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_num_requested' },
-{ oid => '6327',
+{ oid => '6349',
+ descr => 'statistics: number of checkpoints performed by the checkpointer',
+ proname => 'pg_stat_get_checkpointer_num_performed',
+ provolatile => 's', proparallel => 'r', prorettype => 'int8',
+ proargtypes => '',
+ prosrc => 'pg_stat_get_checkpointer_num_performed' },
+{ oid => '6350',
descr => 'statistics: number of timed restartpoints started by the checkpointer',
proname => 'pg_stat_get_checkpointer_restartpoints_timed', provolatile => 's',
proparallel => 'r', prorettype => 'int8', proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_restartpoints_timed' },
-{ oid => '6328',
+{ oid => '6351',
descr => 'statistics: number of backend requested restartpoints started by the checkpointer',
proname => 'pg_stat_get_checkpointer_restartpoints_requested',
provolatile => 's', proparallel => 'r', prorettype => 'int8',
proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_restartpoints_requested' },
-{ oid => '6329',
+{ oid => '6352',
descr => 'statistics: number of backend performed restartpoints',
proname => 'pg_stat_get_checkpointer_restartpoints_performed',
provolatile => 's', proparallel => 'r', prorettype => 'int8',
proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_restartpoints_performed' },
-{ oid => '2771',
+{ oid => '6353',
descr => 'statistics: number of buffers written during checkpoints and restartpoints',
proname => 'pg_stat_get_checkpointer_buffers_written', provolatile => 's',
proparallel => 'r', prorettype => 'int8', proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_buffers_written' },
-{ oid => '6314', descr => 'statistics: last reset for the checkpointer',
+{ oid => '6354', descr => 'statistics: last reset for the checkpointer',
proname => 'pg_stat_get_checkpointer_stat_reset_time', provolatile => 's',
proparallel => 'r', prorettype => 'timestamptz', proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_stat_reset_time' },
+{ oid => '6355',
+ descr => 'statistics: checkpoint/restartpoint time spent writing buffers to disk, in milliseconds',
+ proname => 'pg_stat_get_checkpointer_write_time', provolatile => 's',
+ proparallel => 'r', prorettype => 'float8', proargtypes => '',
+ prosrc => 'pg_stat_get_checkpointer_write_time' },
+{ oid => '6356',
+ descr => 'statistics: checkpoint/restartpoint time spent synchronizing buffers to disk, in milliseconds',
+ proname => 'pg_stat_get_checkpointer_sync_time', provolatile => 's',
+ proparallel => 'r', prorettype => 'float8', proargtypes => '',
+ prosrc => 'pg_stat_get_checkpointer_sync_time' },
{ oid => '2772',
descr => 'statistics: number of buffers written by the bgwriter for cleaning dirty buffers',
proname => 'pg_stat_get_bgwriter_buf_written_clean', provolatile => 's',
@@ -5857,16 +5873,6 @@
proname => 'pg_stat_get_bgwriter_stat_reset_time', provolatile => 's',
proparallel => 'r', prorettype => 'timestamptz', proargtypes => '',
prosrc => 'pg_stat_get_bgwriter_stat_reset_time' },
-{ oid => '3160',
- descr => 'statistics: checkpoint/restartpoint time spent writing buffers to disk, in milliseconds',
- proname => 'pg_stat_get_checkpointer_write_time', provolatile => 's',
- proparallel => 'r', prorettype => 'float8', proargtypes => '',
- prosrc => 'pg_stat_get_checkpointer_write_time' },
-{ oid => '3161',
- descr => 'statistics: checkpoint/restartpoint time spent synchronizing buffers to disk, in milliseconds',
- proname => 'pg_stat_get_checkpointer_sync_time', provolatile => 's',
- proparallel => 'r', prorettype => 'float8', proargtypes => '',
- prosrc => 'pg_stat_get_checkpointer_sync_time' },
{ oid => '2859', descr => 'statistics: number of buffer allocations',
proname => 'pg_stat_get_buf_alloc', provolatile => 's', proparallel => 'r',
prorettype => 'int8', proargtypes => '', prosrc => 'pg_stat_get_buf_alloc' },
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 4752dfe7197..476acd680c0 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -294,6 +294,7 @@ typedef struct PgStat_CheckpointerStats
{
PgStat_Counter num_timed;
PgStat_Counter num_requested;
+ PgStat_Counter num_performed;
PgStat_Counter restartpoints_timed;
PgStat_Counter restartpoints_requested;
PgStat_Counter restartpoints_performed;
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index a1626f3fae9..f5434d8365c 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1824,6 +1824,7 @@ pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_cle
pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
pg_stat_checkpointer| SELECT pg_stat_get_checkpointer_num_timed() AS num_timed,
pg_stat_get_checkpointer_num_requested() AS num_requested,
+ pg_stat_get_checkpointer_num_performed() AS num_done,
pg_stat_get_checkpointer_restartpoints_timed() AS restartpoints_timed,
pg_stat_get_checkpointer_restartpoints_requested() AS restartpoints_req,
pg_stat_get_checkpointer_restartpoints_performed() AS restartpoints_done,
--
2.46.0
