From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: pgsql-hackers@lists.postgresql.org
Subject: Remove wal_[sync|write][_time] from pg_stat_wal and track_wal_io_timing
Date: Tue, 18 Feb 2025 10:43:15 +0000
Message-ID: <Z7RkQ0EfYaqqjgz/@ip-10-97-1-34.eu-west-3.compute.internal> (raw)
Hi hackers,
a051e71e28a added the WAL writes and fsyncs information (and their related timing)
into the pg_stat_io view so that one can now find the same information in 2 places:
pg_stat_wal and pg_stat_io (for the wal object). This lead to a discussion in
[1] to remove this information from the pg_stat_wal view.
=== Let's sump up in this dedicated thread what has been discussed in [1]
1. The pg_stat_io's writes and fsyncs (and their relative timing) are incremented
at the exact same places as their pg_stat_wal counterparts.
2. pgstat_tracks_io_bktype() returns false for backend's that do not generate WAL
(so that we don't lost WAL information in pg_stat_io).
3. pg_stat_stat.wal_write is the same value as "select sum(writes)
from pg_stat_io where object = 'wal' and context = 'normal'" as these
are incremented in XLogWrite().
4. Same argument about pg_stat_wal.wal_write_time with
pg_stat_io.write_time.
5. issue_xlog_fsync() tells that pg_stat_wal.wal_sync_time and
sum(pg_stat_io.fsync_time) under object=wal and context=normal are the
same values.
6. Same argument with the fsync counters pg_stat_wal.wal_sync and
pg_stat_io.fsyncs.
7. This will encourage monitoring pull to move to pg_stat_io, where there is much
more context and granularity of the stats data.
8. That will simplify the work done for the per backend WAL statistics ([1])
=== Remarks
R1. The "bytes" fields differ (as pg_stat_wal.wal_bytes somehow "focus" on the wal
records size while the pg_stat_io's unit is the wal_block_size) so we keep them
in both places.
R2. track_wal_io_timing becomes useless once those fields are gone from pg_stat_wal
R3. PendingWalStats becomes empty, so removes it.
=== Patch structure
PFA 3 sub patches:
- 0001: Add details in the pg_stat_io doc about the wal object. That's basically
more or less a copy/paste from the pg_stat_wal fields description that will be
removed in 0002. As we already track them in pg_stat_io, it's done in a dedicated
patch.
- 0002: Remove wal_[sync|write][_time] from pg_stat_wal, PendingWalStats and
track_wal_io_timing. That does not make sense to split this work in sub-patches
so that all of this in done in 0002.
- 0003: remove the pgstat_prepare_io_time() parameter. Now that track_wal_io_timing
is gone there is no need for pgstat_prepare_io_time() to get a parameter.
[1]: https://www.postgresql.org/message-id/Z7NSc5j6M4g2r1HD%40ip-10-97-1-34.eu-west-3.compute.internal
Looking forward to your feedback,
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.comAttachments:download all (3 files, .tar.gz)v1-0001-Add-details-in-the-pg_stat_io-doc-about-the-wal-o.patch (text/x-diff, 2.9K) download
From bc9dec707e2b12a6c6e7d1f654fbe41c8e5bbb65 Mon Sep 17 00:00:00 2001
From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Date: Tue, 18 Feb 2025 07:14:05 +0000
Subject: [PATCH v1 1/3] Add details in the pg_stat_io doc about the wal object
Adding details about writes, fsyncs, write_time and sync_time when linked
to the wal object. Same level of details as for wal_write, wal_sync, wal_write_time
and wal_sync_time in pg_stat_wal.
---
doc/src/sgml/monitoring.sgml | 42 ++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
100.0% doc/src/sgml/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgmlindex 928a6eb64b0..2c61c0d1e50 100644--- a/doc/src/sgml/monitoring.sgml+++ b/doc/src/sgml/monitoring.sgml@@ -2930,6 +2930,48 @@ description | Waiting for a newly initialized WAL file to reach durable storage
writer</literal>.
</para>
+ <para>+ For the <literal>wal</literal> <structfield>object</structfield>:+ <itemizedlist>+ <listitem>+ <para>+ <structfield>writes</structfield> is the number of times WAL buffers were+ written out to disk via <function>XLogWrite</function> request.+ See <xref linkend="wal-configuration"/> for more information about the internal+ WAL function <function>XLogWrite</function>.+ </para>+ </listitem>+ <listitem>+ <para>+ <structfield>fsyncs</structfield> is the number of times WAL files were+ synced to disk via <function>issue_xlog_fsync</function> request (if <xref linkend="guc-fsync"/>+ is <literal>on</literal> and <xref linkend="guc-wal-sync-method"/> is either+ <literal>fdatasync</literal>, <literal>fsync</literal> or <literal>fsync_writethrough</literal>,+ otherwise zero). See <xref linkend="wal-configuration"/> for more information+ about the internal WAL function <function>issue_xlog_fsync</function>.+ </para>+ </listitem>+ <listitem>+ <para>+ <structfield>write_time</structfield> is the total amount of time spent writing+ WAL buffers to disk via <function>XLogWrite</function> request.+ This includes the sync time when <varname>wal_sync_method</varname>+ is either <literal>open_datasync</literal> or <literal>open_sync</literal>.+ </para>+ </listitem>+ <listitem>+ <para>+ <structfield>sync_time</structfield> is the total amount of time spent syncing+ WAL files to disk via <function>issue_xlog_fsync</function> request (if+ <varname>fsync</varname> is <literal>on</literal>,+ and <varname>wal_sync_method</varname> is either <literal>fdatasync</literal>,+ <literal>fsync</literal> or <literal>fsync_writethrough</literal>,+ otherwise zero).+ </para>+ </listitem>+ </itemizedlist>+ </para>+
<para>
<structname>pg_stat_io</structname> can be used to inform database tuning.
For example:
--
2.34.1
v1-0002-Remove-wal_-sync-write-_time-from-pg_stat_wal-and.patch (text/x-diff, 20.1K) download
From 42b2d46d80f082829c91f9c91f844ab750f2cafd Mon Sep 17 00:00:00 2001
From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Date: Tue, 18 Feb 2025 07:58:24 +0000
Subject: [PATCH v1 2/3] Remove wal_[sync|write][_time] from pg_stat_wal and
track_wal_io_timing
a051e71e28a added this information into pg_stat_io (with more details and
granularity), so there is no need to keep it in pg_stat_wal. This also
allows to remove PendingWalStats and simplifies up coming commits related
to per backend WAL statistics. Once done, track_wal_io_timing becomes useless
so it is also removed.
---
doc/src/sgml/config.sgml | 22 -------
doc/src/sgml/monitoring.sgml | 62 -------------------
doc/src/sgml/wal.sgml | 12 ++--
src/backend/access/transam/xlog.c | 38 ++----------
src/backend/catalog/system_views.sql | 4 --
src/backend/utils/activity/pgstat_wal.c | 24 +------
src/backend/utils/adt/pgstatfuncs.c | 20 +-----
src/backend/utils/misc/guc_tables.c | 9 ---
src/backend/utils/misc/postgresql.conf.sample | 1 -
src/include/access/xlog.h | 1 -
src/include/catalog/pg_proc.dat | 6 +-
src/include/pgstat.h | 28 ---------
src/test/regress/expected/rules.out | 6 +-
src/tools/pgindent/typedefs.list | 1 -
14 files changed, 19 insertions(+), 215 deletions(-)
48.6% doc/src/sgml/
12.7% src/backend/access/transam/
11.1% src/backend/utils/activity/
10.6% src/backend/utils/adt/
3.4% src/backend/
3.2% src/include/catalog/
7.9% src/include/
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgmlindex 336630ce417..05760241174 100644--- a/doc/src/sgml/config.sgml+++ b/doc/src/sgml/config.sgml@@ -8327,28 +8327,6 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
</listitem>
</varlistentry>
- <varlistentry id="guc-track-wal-io-timing" xreflabel="track_wal_io_timing">- <term><varname>track_wal_io_timing</varname> (<type>boolean</type>)- <indexterm>- <primary><varname>track_wal_io_timing</varname> configuration parameter</primary>- </indexterm>- </term>- <listitem>- <para>- Enables timing of WAL I/O calls. This parameter is off by default,- as it will repeatedly query the operating system for the current time,- which may cause significant overhead on some platforms.- You can use the <application>pg_test_timing</application> tool to- measure the overhead of timing on your system.- I/O timing information is- displayed in <link linkend="monitoring-pg-stat-wal-view">- <structname>pg_stat_wal</structname></link>.- Only superusers and users with the appropriate <literal>SET</literal>- privilege can change this setting.- </para>- </listitem>- </varlistentry>-
<varlistentry id="guc-track-functions" xreflabel="track_functions">
<term><varname>track_functions</varname> (<type>enum</type>)
<indexterm>
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgmlindex 2c61c0d1e50..8cbc89aa797 100644--- a/doc/src/sgml/monitoring.sgml+++ b/doc/src/sgml/monitoring.sgml@@ -183,11 +183,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
of block read, write, extend, and fsync times.
</para>
- <para>- The parameter <xref linkend="guc-track-wal-io-timing"/> enables monitoring- of WAL write and fsync times.- </para>-
<para>
Normally these parameters are set in <filename>postgresql.conf</filename> so
that they apply to all server processes, but it is possible to turn
@@ -3297,63 +3292,6 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
- <row>- <entry role="catalog_table_entry"><para role="column_definition">- <structfield>wal_write</structfield> <type>bigint</type>- </para>- <para>- Number of times WAL buffers were written out to disk via- <function>XLogWrite</function> request.- See <xref linkend="wal-configuration"/> for more information about- the internal WAL function <function>XLogWrite</function>.- </para></entry>- </row>-- <row>- <entry role="catalog_table_entry"><para role="column_definition">- <structfield>wal_sync</structfield> <type>bigint</type>- </para>- <para>- Number of times WAL files were synced to disk via- <function>issue_xlog_fsync</function> request- (if <xref linkend="guc-fsync"/> is <literal>on</literal> and- <xref linkend="guc-wal-sync-method"/> is either- <literal>fdatasync</literal>, <literal>fsync</literal> or- <literal>fsync_writethrough</literal>, otherwise zero).- See <xref linkend="wal-configuration"/> for more information about- the internal WAL function <function>issue_xlog_fsync</function>.- </para></entry>- </row>-- <row>- <entry role="catalog_table_entry"><para role="column_definition">- <structfield>wal_write_time</structfield> <type>double precision</type>- </para>- <para>- Total amount of time spent writing WAL buffers to disk via- <function>XLogWrite</function> request, in milliseconds- (if <xref linkend="guc-track-wal-io-timing"/> is enabled,- otherwise zero). This includes the sync time when- <varname>wal_sync_method</varname> is either- <literal>open_datasync</literal> or <literal>open_sync</literal>.- </para></entry>- </row>-- <row>- <entry role="catalog_table_entry"><para role="column_definition">- <structfield>wal_sync_time</structfield> <type>double precision</type>- </para>- <para>- Total amount of time spent syncing WAL files to disk via- <function>issue_xlog_fsync</function> request, in milliseconds- (if <varname>track_wal_io_timing</varname> is enabled,- <varname>fsync</varname> is <literal>on</literal>, and- <varname>wal_sync_method</varname> is either- <literal>fdatasync</literal>, <literal>fsync</literal> or- <literal>fsync_writethrough</literal>, otherwise zero).- </para></entry>- </row>-
<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>stats_reset</structfield> <type>timestamp with time zone</type>
diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgmlindex b908720adea..8f3ac982b0e 100644--- a/doc/src/sgml/wal.sgml+++ b/doc/src/sgml/wal.sgml@@ -810,11 +810,11 @@
<para>
There are two internal functions to write WAL data to disk:
<function>XLogWrite</function> and <function>issue_xlog_fsync</function>.
- When <xref linkend="guc-track-wal-io-timing"/> is enabled, the total+ When <xref linkend="guc-track-io-timing"/> is enabled, the total
amounts of time <function>XLogWrite</function> writes and
<function>issue_xlog_fsync</function> syncs WAL data to disk are counted as
- <literal>wal_write_time</literal> and <literal>wal_sync_time</literal> in- <xref linkend="pg-stat-wal-view"/>, respectively.+ <literal>write_time</literal> and <literal>sync_time</literal> in+ <xref linkend="pg-stat-io-view"/> for the wal <literal>object</literal>, respectively.
<function>XLogWrite</function> is normally called by
<function>XLogInsertRecord</function> (when there is no space for the new
record in WAL buffers), <function>XLogFlush</function> and the WAL writer,
@@ -829,11 +829,11 @@
<literal>fsync</literal>, or <literal>fsync_writethrough</literal>,
the write operation moves WAL buffers to kernel cache and
<function>issue_xlog_fsync</function> syncs them to disk. Regardless
- of the setting of <varname>track_wal_io_timing</varname>, the number+ of the setting of <varname>track_io_timing</varname>, the number
of times <function>XLogWrite</function> writes and
<function>issue_xlog_fsync</function> syncs WAL data to disk are also
- counted as <literal>wal_write</literal> and <literal>wal_sync</literal>- in <structname>pg_stat_wal</structname>, respectively.+ counted as <literal>writes</literal> and <literal>fsyncs</literal>+ in <structname>pg_stat_io</structname> for the wal <literal>object</literal>, respectively.
</para>
<para>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.cindex 25a5c605404..5a1940a42f5 100644--- a/src/backend/access/transam/xlog.c+++ b/src/backend/access/transam/xlog.c@@ -134,7 +134,6 @@ int CommitSiblings = 5; /* # concurrent xacts needed to sleep */
int wal_retrieve_retry_interval = 5000;
int max_slot_wal_keep_size_mb = -1;
int wal_decode_buffer_size = 512 * 1024;
-bool track_wal_io_timing = false;
#ifdef WAL_DEBUG
bool XLOG_DEBUG = false;
@@ -2436,10 +2435,9 @@ XLogWrite(XLogwrtRqst WriteRqst, TimeLineID tli, bool flexible)
errno = 0;
/*
- * Measure I/O timing to write WAL data, for pg_stat_io and/or- * pg_stat_wal.+ * Measure I/O timing to write WAL data, for pg_stat_io.
*/
- start = pgstat_prepare_io_time(track_io_timing || track_wal_io_timing);+ start = pgstat_prepare_io_time(track_io_timing);
pgstat_report_wait_start(WAIT_EVENT_WAL_WRITE);
written = pg_pwrite(openLogFile, from, nleft, startoffset);
@@ -2448,20 +2446,6 @@ XLogWrite(XLogwrtRqst WriteRqst, TimeLineID tli, bool flexible)
pgstat_count_io_op_time(IOOBJECT_WAL, IOCONTEXT_NORMAL,
IOOP_WRITE, start, 1, written);
- /*- * Increment the I/O timing and the number of times WAL data- * were written out to disk.- */- if (track_wal_io_timing)- {- instr_time end;-- INSTR_TIME_SET_CURRENT(end);- INSTR_TIME_ACCUM_DIFF(PendingWalStats.wal_write_time, end, start);- }-- PendingWalStats.wal_write++;-
if (written <= 0)
{
char xlogfname[MAXFNAMELEN];
@@ -8718,10 +8702,9 @@ issue_xlog_fsync(int fd, XLogSegNo segno, TimeLineID tli)
return;
/*
- * Measure I/O timing to sync the WAL file for pg_stat_io and/or- * pg_stat_wal.+ * Measure I/O timing to sync the WAL file for pg_stat_io.
*/
- start = pgstat_prepare_io_time(track_io_timing || track_wal_io_timing);+ start = pgstat_prepare_io_time(track_io_timing);
pgstat_report_wait_start(WAIT_EVENT_WAL_SYNC);
switch (wal_sync_method)
@@ -8767,21 +8750,8 @@ issue_xlog_fsync(int fd, XLogSegNo segno, TimeLineID tli)
pgstat_report_wait_end();
- /*- * Increment the I/O timing and the number of times WAL files were synced.- */- if (track_wal_io_timing)- {- instr_time end;-- INSTR_TIME_SET_CURRENT(end);- INSTR_TIME_ACCUM_DIFF(PendingWalStats.wal_sync_time, end, start);- }-
pgstat_count_io_op_time(IOOBJECT_WAL, IOCONTEXT_NORMAL, IOOP_FSYNC,
start, 1, 0);
-- PendingWalStats.wal_sync++;
}
/*
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sqlindex eff0990957e..a4d2cfdcaf5 100644--- a/src/backend/catalog/system_views.sql+++ b/src/backend/catalog/system_views.sql@@ -1189,10 +1189,6 @@ CREATE VIEW pg_stat_wal AS
w.wal_fpi,
w.wal_bytes,
w.wal_buffers_full,
- w.wal_write,- w.wal_sync,- w.wal_write_time,- w.wal_sync_time,
w.stats_reset
FROM pg_stat_get_wal() w;
diff --git a/src/backend/utils/activity/pgstat_wal.c b/src/backend/utils/activity/pgstat_wal.cindex c1ca65eb991..4dc41a4a590 100644--- a/src/backend/utils/activity/pgstat_wal.c+++ b/src/backend/utils/activity/pgstat_wal.c@@ -21,8 +21,6 @@
#include "utils/pgstat_internal.h"
-PgStat_PendingWalStats PendingWalStats = {0};-
/*
* WAL usage counters saved from pgWalUsage at the previous call to
* pgstat_report_wal(). This is used to calculate how much WAL usage
@@ -118,17 +116,10 @@ pgstat_wal_flush_cb(bool nowait)
#define WALSTAT_ACC(fld, var_to_add) \
(stats_shmem->stats.fld += var_to_add.fld)
-#define WALSTAT_ACC_INSTR_TIME(fld) \- (stats_shmem->stats.fld += INSTR_TIME_GET_MICROSEC(PendingWalStats.fld))
WALSTAT_ACC(wal_records, wal_usage_diff);
WALSTAT_ACC(wal_fpi, wal_usage_diff);
WALSTAT_ACC(wal_bytes, wal_usage_diff);
WALSTAT_ACC(wal_buffers_full, wal_usage_diff);
- WALSTAT_ACC(wal_write, PendingWalStats);- WALSTAT_ACC(wal_sync, PendingWalStats);- WALSTAT_ACC_INSTR_TIME(wal_write_time);- WALSTAT_ACC_INSTR_TIME(wal_sync_time);-#undef WALSTAT_ACC_INSTR_TIME
#undef WALSTAT_ACC
LWLockRelease(&stats_shmem->lock);
@@ -138,11 +129,6 @@ pgstat_wal_flush_cb(bool nowait)
*/
prevWalUsage = pgWalUsage;
- /*- * Clear out the statistics buffer, so it can be re-used.- */- MemSet(&PendingWalStats, 0, sizeof(PendingWalStats));-
return false;
}
@@ -158,18 +144,12 @@ pgstat_wal_init_backend_cb(void)
}
/*
- * To determine whether any WAL activity has occurred since last time, not- * only the number of generated WAL records but also the numbers of WAL- * writes and syncs need to be checked. Because even transaction that- * generates no WAL records can write or sync WAL data when flushing the- * data pages.+ * To determine whether WAL usage happened.
*/
bool
pgstat_wal_have_pending_cb(void)
{
- return pgWalUsage.wal_records != prevWalUsage.wal_records ||- PendingWalStats.wal_write != 0 ||- PendingWalStats.wal_sync != 0;+ return pgWalUsage.wal_records != prevWalUsage.wal_records;
}
void
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.cindex e9096a88492..68e16e52ab6 100644--- a/src/backend/utils/adt/pgstatfuncs.c+++ b/src/backend/utils/adt/pgstatfuncs.c@@ -1637,7 +1637,7 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
Datum
pg_stat_get_wal(PG_FUNCTION_ARGS)
{
-#define PG_STAT_GET_WAL_COLS 9+#define PG_STAT_GET_WAL_COLS 5
TupleDesc tupdesc;
Datum values[PG_STAT_GET_WAL_COLS] = {0};
bool nulls[PG_STAT_GET_WAL_COLS] = {0};
@@ -1654,15 +1654,7 @@ pg_stat_get_wal(PG_FUNCTION_ARGS)
NUMERICOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 4, "wal_buffers_full",
INT8OID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 5, "wal_write",- INT8OID, -1, 0);- TupleDescInitEntry(tupdesc, (AttrNumber) 6, "wal_sync",- INT8OID, -1, 0);- TupleDescInitEntry(tupdesc, (AttrNumber) 7, "wal_write_time",- FLOAT8OID, -1, 0);- TupleDescInitEntry(tupdesc, (AttrNumber) 8, "wal_sync_time",- FLOAT8OID, -1, 0);- TupleDescInitEntry(tupdesc, (AttrNumber) 9, "stats_reset",+ TupleDescInitEntry(tupdesc, (AttrNumber) 5, "stats_reset",
TIMESTAMPTZOID, -1, 0);
BlessTupleDesc(tupdesc);
@@ -1682,14 +1674,8 @@ pg_stat_get_wal(PG_FUNCTION_ARGS)
Int32GetDatum(-1));
values[3] = Int64GetDatum(wal_stats->wal_buffers_full);
- values[4] = Int64GetDatum(wal_stats->wal_write);- values[5] = Int64GetDatum(wal_stats->wal_sync);-- /* Convert counters from microsec to millisec for display */- values[6] = Float8GetDatum(((double) wal_stats->wal_write_time) / 1000.0);- values[7] = Float8GetDatum(((double) wal_stats->wal_sync_time) / 1000.0);- values[8] = TimestampTzGetDatum(wal_stats->stat_reset_timestamp);+ values[4] = TimestampTzGetDatum(wal_stats->stat_reset_timestamp);
/* Returns the record as Datum */
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.cindex cce73314609..6d4cf7609a7 100644--- a/src/backend/utils/misc/guc_tables.c+++ b/src/backend/utils/misc/guc_tables.c@@ -1499,15 +1499,6 @@ struct config_bool ConfigureNamesBool[] =
false,
NULL, NULL, NULL
},
- {- {"track_wal_io_timing", PGC_SUSET, STATS_CUMULATIVE,- gettext_noop("Collects timing statistics for WAL I/O activity."),- NULL- },- &track_wal_io_timing,- false,- NULL, NULL, NULL- },
{
{"update_process_title", PGC_SUSET, PROCESS_TITLE,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sampleindex d472987ed46..c64b3e8a0e6 100644--- a/src/backend/utils/misc/postgresql.conf.sample+++ b/src/backend/utils/misc/postgresql.conf.sample@@ -637,7 +637,6 @@
#track_counts = on
#track_cost_delay_timing = off
#track_io_timing = off
-#track_wal_io_timing = off
#track_functions = none # none, pl, all
#stats_fetch_consistency = cache # cache, none, snapshot
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.hindex 4411c1468ac..bd18d95a6cf 100644--- a/src/include/access/xlog.h+++ b/src/include/access/xlog.h@@ -54,7 +54,6 @@ extern PGDLLIMPORT char *wal_consistency_checking_string;
extern PGDLLIMPORT bool log_checkpoints;
extern PGDLLIMPORT int CommitDelay;
extern PGDLLIMPORT int CommitSiblings;
-extern PGDLLIMPORT bool track_wal_io_timing;
extern PGDLLIMPORT int wal_decode_buffer_size;
extern PGDLLIMPORT int CheckPointSegments;
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.datindex 9e803d610d7..1e1626964e3 100644--- a/src/include/catalog/pg_proc.dat+++ b/src/include/catalog/pg_proc.dat@@ -5950,9 +5950,9 @@
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
- proallargtypes => '{int8,int8,numeric,int8,int8,int8,float8,float8,timestamptz}',- proargmodes => '{o,o,o,o,o,o,o,o,o}',- proargnames => '{wal_records,wal_fpi,wal_bytes,wal_buffers_full,wal_write,wal_sync,wal_write_time,wal_sync_time,stats_reset}',+ proallargtypes => '{int8,int8,numeric,int8,timestamptz}',+ proargmodes => '{o,o,o,o,o}',+ proargnames => '{wal_records,wal_fpi,wal_bytes,wal_buffers_full,stats_reset}',
prosrc => 'pg_stat_get_wal' },
{ oid => '6248', descr => 'statistics: information about WAL prefetching',
proname => 'pg_stat_get_recovery_prefetch', prorows => '1', proretset => 't',
diff --git a/src/include/pgstat.h b/src/include/pgstat.hindex 53f2a8458e6..a3a341cc604 100644--- a/src/include/pgstat.h+++ b/src/include/pgstat.h@@ -480,28 +480,9 @@ typedef struct PgStat_WalStats
PgStat_Counter wal_fpi;
uint64 wal_bytes;
PgStat_Counter wal_buffers_full;
- PgStat_Counter wal_write;- PgStat_Counter wal_sync;- PgStat_Counter wal_write_time;- PgStat_Counter wal_sync_time;
TimestampTz stat_reset_timestamp;
} PgStat_WalStats;
-/*- * This struct stores wal-related durations as instr_time, which makes it- * cheaper and easier to accumulate them, by not requiring type- * conversions. During stats flush instr_time will be converted into- * microseconds.- */-typedef struct PgStat_PendingWalStats-{- PgStat_Counter wal_write;- PgStat_Counter wal_sync;- instr_time wal_write_time;- instr_time wal_sync_time;-} PgStat_PendingWalStats;--
/*
* Functions in pgstat.c
*/
@@ -834,13 +815,4 @@ extern PGDLLIMPORT PgStat_Counter pgStatTransactionIdleTime;
/* updated by the traffic cop and in errfinish() */
extern PGDLLIMPORT SessionEndType pgStatSessionEndCause;
--/*- * Variables in pgstat_wal.c- */--/* updated directly by backends and background processes */-extern PGDLLIMPORT PgStat_PendingWalStats PendingWalStats;--
#endif /* PGSTAT_H */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.outindex 5baba8d39ff..62f69ac20b2 100644--- a/src/test/regress/expected/rules.out+++ b/src/test/regress/expected/rules.out@@ -2259,12 +2259,8 @@ pg_stat_wal| SELECT wal_records,
wal_fpi,
wal_bytes,
wal_buffers_full,
- wal_write,- wal_sync,- wal_write_time,- wal_sync_time,
stats_reset
- FROM pg_stat_get_wal() w(wal_records, wal_fpi, wal_bytes, wal_buffers_full, wal_write, wal_sync, wal_write_time, wal_sync_time, stats_reset);+ FROM pg_stat_get_wal() w(wal_records, wal_fpi, wal_bytes, wal_buffers_full, stats_reset);
pg_stat_wal_receiver| SELECT pid,
status,
receive_start_lsn,
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.listindex bce4214503d..740777127e9 100644--- a/src/tools/pgindent/typedefs.list+++ b/src/tools/pgindent/typedefs.list@@ -2163,7 +2163,6 @@ PgStat_KindInfo
PgStat_LocalState
PgStat_PendingDroppedStatsItem
PgStat_PendingIO
-PgStat_PendingWalStats
PgStat_SLRUStats
PgStat_ShmemControl
PgStat_Snapshot
--
2.34.1
v1-0003-remove-the-pgstat_prepare_io_time-parameter.patch (text/x-diff, 8.3K) download
From 6f878f1bbfb119b1dbe95b4cb26b30c97b7a047e Mon Sep 17 00:00:00 2001
From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Date: Tue, 18 Feb 2025 08:52:41 +0000
Subject: [PATCH v1 3/3] remove the pgstat_prepare_io_time() parameter
Now that track_wal_io_timing is gone there is no need for pgstat_prepare_io_time()
to get a parameter.
---
src/backend/access/transam/xlog.c | 8 ++++----
src/backend/access/transam/xlogreader.c | 2 +-
src/backend/access/transam/xlogrecovery.c | 2 +-
src/backend/storage/buffer/bufmgr.c | 10 +++++-----
src/backend/storage/buffer/localbuf.c | 4 ++--
src/backend/storage/smgr/md.c | 4 ++--
src/backend/utils/activity/pgstat_io.c | 7 +++----
src/include/pgstat.h | 2 +-
8 files changed, 19 insertions(+), 20 deletions(-)
31.1% src/backend/access/transam/
37.2% src/backend/storage/buffer/
10.5% src/backend/storage/smgr/
14.7% src/backend/utils/activity/
6.2% src/include/
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.cindex 5a1940a42f5..24624c84748 100644--- a/src/backend/access/transam/xlog.c+++ b/src/backend/access/transam/xlog.c@@ -2437,7 +2437,7 @@ XLogWrite(XLogwrtRqst WriteRqst, TimeLineID tli, bool flexible)
/*
* Measure I/O timing to write WAL data, for pg_stat_io.
*/
- start = pgstat_prepare_io_time(track_io_timing);+ start = pgstat_prepare_io_time();
pgstat_report_wait_start(WAIT_EVENT_WAL_WRITE);
written = pg_pwrite(openLogFile, from, nleft, startoffset);
@@ -3248,7 +3248,7 @@ XLogFileInitInternal(XLogSegNo logsegno, TimeLineID logtli,
errmsg("could not create file \"%s\": %m", tmppath)));
/* Measure I/O timing when initializing segment */
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
pgstat_report_wait_start(WAIT_EVENT_WAL_INIT_WRITE);
save_errno = 0;
@@ -3310,7 +3310,7 @@ XLogFileInitInternal(XLogSegNo logsegno, TimeLineID logtli,
}
/* Measure I/O timing when flushing segment */
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
pgstat_report_wait_start(WAIT_EVENT_WAL_INIT_SYNC);
if (pg_fsync(fd) != 0)
@@ -8704,7 +8704,7 @@ issue_xlog_fsync(int fd, XLogSegNo segno, TimeLineID tli)
/*
* Measure I/O timing to sync the WAL file for pg_stat_io.
*/
- start = pgstat_prepare_io_time(track_io_timing);+ start = pgstat_prepare_io_time();
pgstat_report_wait_start(WAIT_EVENT_WAL_SYNC);
switch (wal_sync_method)
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.cindex 31bffc6f501..995e4f7c26f 100644--- a/src/backend/access/transam/xlogreader.c+++ b/src/backend/access/transam/xlogreader.c@@ -1557,7 +1557,7 @@ WALRead(XLogReaderState *state,
#ifndef FRONTEND
/* Measure I/O timing when reading segment */
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
pgstat_report_wait_start(WAIT_EVENT_WAL_READ);
#endif
diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.cindex 473de6710d7..ac70b73749c 100644--- a/src/backend/access/transam/xlogrecovery.c+++ b/src/backend/access/transam/xlogrecovery.c@@ -3401,7 +3401,7 @@ retry:
readOff = targetPageOff;
/* Measure I/O timing when reading segment */
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
pgstat_report_wait_start(WAIT_EVENT_WAL_READ);
r = pg_pread(readFile, readBuf, XLOG_BLCKSZ, (off_t) readOff);
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.cindex 80b0d0c5ded..e880bed4627 100644--- a/src/backend/storage/buffer/bufmgr.c+++ b/src/backend/storage/buffer/bufmgr.c@@ -1509,7 +1509,7 @@ WaitReadBuffers(ReadBuffersOperation *operation)
io_pages[io_buffers_len++] = BufferGetBlock(buffers[i]);
}
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
smgrreadv(operation->smgr, forknum, io_first_block, io_pages, io_buffers_len);
pgstat_count_io_op_time(io_object, io_context, IOOP_READ, io_start,
1, io_buffers_len * BLCKSZ);
@@ -2401,7 +2401,7 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
}
}
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
/*
* Note: if smgrzeroextend fails, we will end up with buffers that are
@@ -3858,7 +3858,7 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
*/
bufToWrite = PageSetChecksumCopy((Page) bufBlock, buf->tag.blockNum);
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
/*
* bufToWrite is either the shared buffer or a copy, as appropriate.
@@ -4459,7 +4459,7 @@ FlushRelationBuffers(Relation rel)
PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
smgrwrite(srel,
BufTagGetForkNum(&bufHdr->tag),
@@ -5916,7 +5916,7 @@ IssuePendingWritebacks(WritebackContext *wb_context, IOContext io_context)
sort_pending_writebacks(wb_context->pending_writebacks,
wb_context->nr_pending);
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
/*
* Coalesce neighbouring writes, but nothing else. For that we iterate
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.cindex 64931efaa75..78b65fb160a 100644--- a/src/backend/storage/buffer/localbuf.c+++ b/src/backend/storage/buffer/localbuf.c@@ -244,7 +244,7 @@ GetLocalVictimBuffer(void)
PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
/* And write... */
smgrwrite(oreln,
@@ -414,7 +414,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
}
}
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
/* actually extend relation */
smgrzeroextend(bmr.smgr, fork, first_block, extend_by, false);
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.cindex 7bf0b45e2c3..298754d1b64 100644--- a/src/backend/storage/smgr/md.c+++ b/src/backend/storage/smgr/md.c@@ -1381,7 +1381,7 @@ register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
ereport(DEBUG1,
(errmsg_internal("could not forward fsync request because request queue is full")));
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
if (FileSync(seg->mdfd_vfd, WAIT_EVENT_DATA_FILE_SYNC) < 0)
ereport(data_sync_elevel(ERROR),
@@ -1786,7 +1786,7 @@ mdsyncfiletag(const FileTag *ftag, char *path)
need_to_close = true;
}
- io_start = pgstat_prepare_io_time(track_io_timing);+ io_start = pgstat_prepare_io_time();
/* Sync the file. */
result = FileSync(file, WAIT_EVENT_DATA_FILE_SYNC);
diff --git a/src/backend/utils/activity/pgstat_io.c b/src/backend/utils/activity/pgstat_io.cindex 28a431084b8..e7362b52a37 100644--- a/src/backend/utils/activity/pgstat_io.c+++ b/src/backend/utils/activity/pgstat_io.c@@ -83,15 +83,14 @@ pgstat_count_io_op(IOObject io_object, IOContext io_context, IOOp io_op,
}
/*
- * Initialize the internal timing for an IO operation, depending on an- * IO timing GUC.+ * Initialize the internal timing for an IO operation.
*/
instr_time
-pgstat_prepare_io_time(bool track_io_guc)+pgstat_prepare_io_time(void)
{
instr_time io_start;
- if (track_io_guc)+ if (track_io_timing)
INSTR_TIME_SET_CURRENT(io_start);
else
{
diff --git a/src/include/pgstat.h b/src/include/pgstat.hindex a3a341cc604..030b101028f 100644--- a/src/include/pgstat.h+++ b/src/include/pgstat.h@@ -564,7 +564,7 @@ extern bool pgstat_bktype_io_stats_valid(PgStat_BktypeIO *backend_io,
BackendType bktype);
extern void pgstat_count_io_op(IOObject io_object, IOContext io_context,
IOOp io_op, uint32 cnt, uint64 bytes);
-extern instr_time pgstat_prepare_io_time(bool track_io_guc);+extern instr_time pgstat_prepare_io_time(void);
extern void pgstat_count_io_op_time(IOObject io_object, IOContext io_context,
IOOp io_op, instr_time start_time,
uint32 cnt, uint64 bytes);
--
2.34.1
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: bertranddrouvot.pg@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Remove wal_[sync|write][_time] from pg_stat_wal and track_wal_io_timing
In-Reply-To: <Z7RkQ0EfYaqqjgz/@ip-10-97-1-34.eu-west-3.compute.internal>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox