database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-07 00:36:50 +03:00
Code Activity

Fix inconsistent reporting of checkpointer stats.

Browse Source 
Previously, the pg_stat_checkpointer view and the checkpoint completion
log message could show different numbers for buffers written
during checkpoints. The view only counted shared buffers,
while the log message included both shared and SLRU buffers,
causing inconsistencies.

This commit resolves the issue by updating both the view and the log message
to separately report shared and SLRU buffers written during checkpoints.
A new slru_written column is added to the pg_stat_checkpointer view
to track SLRU buffers, while the existing buffers_written column now
tracks only shared buffers. This change would help users distinguish
between the two types of buffers, in the pg_stat_checkpointer view and
the checkpoint complete log message, respectively.

Bump catalog version.

Author: Nitin Jadhav
Reviewed-by: Bharath Rupireddy, Michael Paquier, Kyotaro Horiguchi, Robert Haas
Reviewed-by: Andres Freund, vignesh C, Fujii Masao
Discussion: https://postgr.es/m/CAMm1aWb18EpT0whJrjG+-nyhNouXET6ZUw0pNYYAe+NezpvsAA@mail.gmail.com
This commit is contained in:
Fujii Masao
2024-10-02 11:17:47 +09:00
parent 506eede711
commit 17cc5f666f
11 changed files with 47 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
doc/src/sgml/monitoring.sgml
View File

@ -3127,7 +3127,16 @@ description | Waiting for a newly initialized WAL file to reach durable storage
<structfield>buffers_written</structfield> <type>bigint</type>
</para>
<para>
Number of buffers written during checkpoints and restartpoints
Number of shared buffers written during checkpoints and restartpoints
</para></entry>
</row>
<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>slru_written</structfield> <type>bigint</type>
</para>
<para>
Number of SLRU buffers written during checkpoints and restartpoints
</para></entry>
</row>

7
src/backend/access/transam/slru.c
View File

@ -716,9 +716,12 @@ SlruInternalWritePage(SlruCtl ctl, int slotno, SlruWriteAll fdata)
if (!ok)
SlruReportIOError(ctl, pageno, InvalidTransactionId);
/* If part of a checkpoint, count this as a buffer written. */
/* If part of a checkpoint, count this as a SLRU buffer written. */
if (fdata)
CheckpointStats.ckpt_bufs_written++;
{
CheckpointStats.ckpt_slru_written++;
PendingCheckpointerStats.slru_written++;
}
}
/*

26
src/backend/access/transam/xlog.c
View File

@ -6727,14 +6727,15 @@ LogCheckpointEnd(bool restartpoint)
*/
if (restartpoint)
ereport(LOG,
(errmsg("restartpoint complete: wrote %d buffers (%.1f%%); "
"%d WAL file(s) added, %d removed, %d recycled; "
"write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s; "
"sync files=%d, longest=%ld.%03d s, average=%ld.%03d s; "
"distance=%d kB, estimate=%d kB; "
"lsn=%X/%X, redo lsn=%X/%X",
(errmsg("restartpoint complete: wrote %d buffers (%.1f%%), "
"wrote %d SLRU buffers; %d WAL file(s) added, "
"%d removed, %d recycled; write=%ld.%03d s, "
"sync=%ld.%03d s, total=%ld.%03d s; sync files=%d, "
"longest=%ld.%03d s, average=%ld.%03d s; distance=%d kB, "
"estimate=%d kB; lsn=%X/%X, redo lsn=%X/%X",
CheckpointStats.ckpt_bufs_written,
(double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers,
CheckpointStats.ckpt_slru_written,
CheckpointStats.ckpt_segs_added,
CheckpointStats.ckpt_segs_removed,
CheckpointStats.ckpt_segs_recycled,
@ -6750,14 +6751,15 @@ LogCheckpointEnd(bool restartpoint)
LSN_FORMAT_ARGS(ControlFile->checkPointCopy.redo))));
else
ereport(LOG,
(errmsg("checkpoint complete: wrote %d buffers (%.1f%%); "
"%d WAL file(s) added, %d removed, %d recycled; "
"write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s; "
"sync files=%d, longest=%ld.%03d s, average=%ld.%03d s; "
"distance=%d kB, estimate=%d kB; "
"lsn=%X/%X, redo lsn=%X/%X",
(errmsg("checkpoint complete: wrote %d buffers (%.1f%%), "
"wrote %d SLRU buffers; %d WAL file(s) added, "
"%d removed, %d recycled; write=%ld.%03d s, "
"sync=%ld.%03d s, total=%ld.%03d s; sync files=%d, "
"longest=%ld.%03d s, average=%ld.%03d s; distance=%d kB, "
"estimate=%d kB; lsn=%X/%X, redo lsn=%X/%X",
CheckpointStats.ckpt_bufs_written,
(double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers,
CheckpointStats.ckpt_slru_written,
CheckpointStats.ckpt_segs_added,
CheckpointStats.ckpt_segs_removed,
CheckpointStats.ckpt_segs_recycled,

1
src/backend/catalog/system_views.sql
View File

@ -1145,6 +1145,7 @@ CREATE VIEW pg_stat_checkpointer AS
pg_stat_get_checkpointer_write_time() AS write_time,
pg_stat_get_checkpointer_sync_time() AS sync_time,
pg_stat_get_checkpointer_buffers_written() AS buffers_written,
pg_stat_get_checkpointer_slru_written() AS slru_written,
pg_stat_get_checkpointer_stat_reset_time() AS stats_reset;
CREATE VIEW pg_stat_io AS

2
src/backend/utils/activity/pgstat_checkpointer.c
View File

@ -56,6 +56,7 @@ pgstat_report_checkpointer(void)
CHECKPOINTER_ACC(write_time);
CHECKPOINTER_ACC(sync_time);
CHECKPOINTER_ACC(buffers_written);
CHECKPOINTER_ACC(slru_written);
#undef CHECKPOINTER_ACC
pgstat_end_changecount_write(&stats_shmem->changecount);
@ -135,5 +136,6 @@ pgstat_checkpointer_snapshot_cb(void)
CHECKPOINTER_COMP(write_time);
CHECKPOINTER_COMP(sync_time);
CHECKPOINTER_COMP(buffers_written);
CHECKPOINTER_COMP(slru_written);
#undef CHECKPOINTER_COMP
}

6
src/backend/utils/adt/pgstatfuncs.c
View File

@ -1221,6 +1221,12 @@ pg_stat_get_checkpointer_buffers_written(PG_FUNCTION_ARGS)
PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->buffers_written);
}
Datum
pg_stat_get_checkpointer_slru_written(PG_FUNCTION_ARGS)
{
PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->slru_written);
}
Datum
pg_stat_get_bgwriter_buf_written_clean(PG_FUNCTION_ARGS)
{

1
src/include/access/xlog.h
View File

@ -167,6 +167,7 @@ typedef struct CheckpointStatsData
TimestampTz ckpt_end_t; /* end of checkpoint */
int ckpt_bufs_written; /* # of buffers written */
int ckpt_slru_written; /* # of SLRU buffers written */
int ckpt_segs_added; /* # of new xlog segments created */
int ckpt_segs_removed; /* # of xlog segments deleted */

2
src/include/catalog/catversion.h
View File

@ -57,6 +57,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 202409302
#define CATALOG_VERSION_NO 202410021
#endif

5
src/include/catalog/pg_proc.dat
View File

@ -5847,6 +5847,11 @@
proname => 'pg_stat_get_checkpointer_buffers_written', provolatile => 's',
proparallel => 'r', prorettype => 'int8', proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_buffers_written' },
{ oid => '8573',
descr => 'statistics: number of SLRU buffers written during checkpoints and restartpoints',
proname => 'pg_stat_get_checkpointer_slru_written', provolatile => 's',
proparallel => 'r', prorettype => 'int8', proargtypes => '',
prosrc => 'pg_stat_get_checkpointer_slru_written' },
{ oid => '6314', descr => 'statistics: last reset for the checkpointer',
proname => 'pg_stat_get_checkpointer_stat_reset_time', provolatile => 's',
proparallel => 'r', prorettype => 'timestamptz', proargtypes => '',

1
src/include/pgstat.h
View File

@ -301,6 +301,7 @@ typedef struct PgStat_CheckpointerStats
PgStat_Counter write_time; /* times in milliseconds */
PgStat_Counter sync_time;
PgStat_Counter buffers_written;
PgStat_Counter slru_written;
TimestampTz stat_reset_timestamp;
} PgStat_CheckpointerStats;

1
src/test/regress/expected/rules.out
View File

@ -1831,6 +1831,7 @@ pg_stat_checkpointer| SELECT pg_stat_get_checkpointer_num_timed() AS num_timed,
pg_stat_get_checkpointer_write_time() AS write_time,
pg_stat_get_checkpointer_sync_time() AS sync_time,
pg_stat_get_checkpointer_buffers_written() AS buffers_written,
pg_stat_get_checkpointer_slru_written() AS slru_written,
pg_stat_get_checkpointer_stat_reset_time() AS stats_reset;
pg_stat_database| SELECT oid AS datid,
datname,