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* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v3 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
---
src/backend/utils/activity/pgstat_backend.c | 57 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
4 files changed, 69 insertions(+), 1 deletion(-)
78.9% src/backend/utils/activity/
11.2% src/include/utils/
9.8% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..bf164854c4b 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,20 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /* Count transaction commit or abort */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..9efc0e10ebf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
--
2.34.1
--u6+Li7FU79Mt/lVd
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v3-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v1] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 2 +
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 160 insertions(+), 1 deletion(-)
26.9% doc/src/sgml/
29.1% src/backend/utils/activity/
12.3% src/backend/utils/adt/
9.7% src/include/catalog/
4.0% src/include/utils/
9.2% src/test/regress/expected/
7.3% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index fa78031ccbb..ef89683164f 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..7cec0c83071 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,13 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static int pgStatBackendXactCommit = 0;
+static int pgStatBackendXactRollback = 0;
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +266,33 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += pgStatBackendXactCommit;
+ shbackendent->stats.xact_rollback += pgStatBackendXactRollback;
+
+ pgStatBackendXactCommit = pgStatBackendXactRollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +317,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +336,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +441,22 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ pgStatBackendXactCommit++;
+ else
+ pgStatBackendXactRollback++;
+
+ backend_has_xactstats = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..4c9f6b0dcec 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--ZnbSmJtA6EgjuGCe--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v2] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
This commit adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
It relies on the existing per backend statistics that has been added in
9aea73fc61d.
---
doc/src/sgml/monitoring.sgml | 36 +++++++++++++
src/backend/utils/activity/pgstat_backend.c | 60 +++++++++++++++++++++
src/backend/utils/activity/pgstat_xact.c | 1 +
src/backend/utils/adt/pgstatfuncs.c | 22 ++++++++
src/include/catalog/pg_proc.dat | 9 ++++
src/include/pgstat.h | 8 +++
src/include/utils/pgstat_internal.h | 4 +-
src/test/regress/expected/stats.out | 17 ++++++
src/test/regress/sql/stats.sql | 10 ++++
9 files changed, 166 insertions(+), 1 deletion(-)
26.1% doc/src/sgml/
29.1% src/backend/utils/activity/
11.9% src/backend/utils/adt/
9.4% src/include/catalog/
3.9% src/include/utils/
3.3% src/include/
8.9% src/test/regress/expected/
7.1% src/test/regress/sql/
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3f4a27a736e..77b41e02b82 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -4921,6 +4921,42 @@ description | Waiting for a newly initialized WAL file to reach durable storage
</para></entry>
</row>
+ <row>
+ <entry id="pg-stat-get-backend-xact-commit" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_commit</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_commit</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been committed by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry id="pg-stat-get-backend-xact-rollback" role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_stat_get_backend_xact_rollback</primary>
+ </indexterm>
+ <function>pg_stat_get_backend_xact_rollback</function> ( <type>integer</type> )
+ <returnvalue>bigint</returnvalue>
+ </para>
+ <para>
+ Returns the number of transactions that have been rolled back by the backend
+ with the specified process ID.
+ </para>
+ <para>
+ The function does not return statistics for the checkpointer,
+ the background writer, the startup process and the autovacuum launcher.
+ </para></entry>
+ </row>
+
<row>
<entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..12ae9a8d321 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+static bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend xact statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * XACT statistics. In this case, avoid unnecessarily modifying the stats
+ * entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some XACT data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
@@ -400,3 +440,23 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
+
+void
+AtEOXact_PgStat_Backend(bool isCommit, bool parallel)
+{
+ /* Don't count parallel worker transaction stats */
+ if (!parallel)
+ {
+ /*
+ * Count transaction commit or abort. (We use counters, not just
+ * bools, in case the reporting message isn't sent right away.)
+ */
+ if (isCommit)
+ PendingBackendStats.pending_xact_commit++;
+ else
+ PendingBackendStats.pending_xact_rollback++;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+ }
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..cd1c501c165 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -42,6 +42,7 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
PgStat_SubXactStatus *xact_state;
AtEOXact_PgStat_Database(isCommit, parallel);
+ AtEOXact_PgStat_Backend(isCommit, parallel);
/* handle transactional stats information */
xact_state = pgStatXactStack;
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index c756c2bebaa..6436129f516 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1606,6 +1606,28 @@ pg_stat_get_backend_io(PG_FUNCTION_ARGS)
return (Datum) 0;
}
+#define PG_STAT_GET_BACKENDENTRY_INT64(stat) \
+Datum \
+CppConcat(pg_stat_get_backend_,stat)(PG_FUNCTION_ARGS) \
+{ \
+ int pid; \
+ PgStat_Backend *backend_stats; \
+ \
+ pid = PG_GETARG_INT32(0); \
+ backend_stats = pgstat_fetch_stat_backend_by_pid(pid, NULL);\
+ \
+ if (!backend_stats) \
+ PG_RETURN_NULL(); \
+ else \
+ PG_RETURN_INT64(backend_stats->stat); \
+}
+
+/* pg_stat_get_backend_xact_commit */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_commit)
+
+/* pg_stat_get_backend_xact_rollback */
+PG_STAT_GET_BACKENDENTRY_INT64(xact_rollback)
+
/*
* pg_stat_wal_build_tuple
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 118d6da1ace..f5085d4e016 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6010,6 +6010,15 @@
proargnames => '{backend_pid,backend_type,object,context,reads,read_bytes,read_time,writes,write_bytes,write_time,writebacks,writeback_time,extends,extend_bytes,extend_time,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}',
prosrc => 'pg_stat_get_backend_io' },
+{ oid => '8170', descr => 'statistics: backend transactions committed',
+ proname => 'pg_stat_get_backend_xact_commit', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_commit' },
+{ oid => '8916', descr => 'statistics: backend transactions rolled back',
+ proname => 'pg_stat_get_backend_xact_rollback', provolatile => 's',
+ proparallel => 'r', prorettype => 'int8', proargtypes => 'int4',
+ prosrc => 'pg_stat_get_backend_xact_rollback' },
+
{ oid => '1136', descr => 'statistics: information about WAL activity',
proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
proparallel => 'r', prorettype => 'record', proargtypes => '',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..d3491faaff2 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Xact statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..23ea8ffd618 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,12 +616,14 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header,
TimestampTz ts);
+extern void AtEOXact_PgStat_Backend(bool isCommit, bool parallel);
/*
* Functions in pgstat_bgwriter.c
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 605f5070376..0d316f94e40 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+ pg_stat_force_next_flush
+--------------------------
+
+(1 row)
+
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+SELECT :xact_commit_after > :xact_commit_before;
+ ?column?
+----------
+ t
+(1 row)
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 54e72866344..d629140d880 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES;
UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
DELETE FROM trunc_stats_test1 WHERE id = 3;
+-- in passing, check that backend's commit is incrementing
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_before
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
BEGIN;
UPDATE trunc_stats_test1 SET id = id + 100;
TRUNCATE trunc_stats_test1;
INSERT INTO trunc_stats_test1 DEFAULT VALUES;
COMMIT;
+SELECT pg_stat_force_next_flush();
+SELECT pg_stat_get_backend_xact_commit AS xact_commit_after
+ FROM pg_stat_get_backend_xact_commit(pg_backend_pid()) \gset
+
+SELECT :xact_commit_after > :xact_commit_before;
+
-- use a savepoint: 1 insert, 1 live
BEGIN;
INSERT INTO trunc_stats_test2 DEFAULT VALUES;
--
2.34.1
--SywurcztURg2uk+W--
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v5 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 7727fed3bda..42bfb9cd38f 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -37,7 +37,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -48,6 +48,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -261,6 +266,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -285,6 +318,10 @@ pgstat_flush_backend(bool nowait, uint32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -300,6 +337,9 @@ pgstat_flush_backend(bool nowait, uint32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index 933dcb5cae5..218ff5e653c 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -352,6 +352,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e3549c3752..5d73c4dfbcf 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -523,6 +523,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -535,6 +537,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -844,6 +852,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index eed4c6b359c..8077c65e938 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -707,7 +707,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, uint32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--uN5gGi2rtCNSVbpC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v5-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH v4 1/3] Adding per backend commit and rollback counters
@ 2025-08-04 08:14 Bertrand Drouvot <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 08:14 UTC (permalink / raw)
It relies on the existing per backend statistics that has been added in
9aea73fc61d. The new pending counters are updated when the database ones are
flushed (to reduce the overhead of incrementing new counters).
---
src/backend/utils/activity/pgstat_backend.c | 42 +++++++++++++++++++-
src/backend/utils/activity/pgstat_database.c | 7 ++++
src/include/pgstat.h | 15 +++++++
src/include/utils/pgstat_internal.h | 3 +-
4 files changed, 65 insertions(+), 2 deletions(-)
74.4% src/backend/utils/activity/
7.8% src/include/utils/
17.7% src/include/
diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c
index 8714a85e2d9..47ce61e5093 100644
--- a/src/backend/utils/activity/pgstat_backend.c
+++ b/src/backend/utils/activity/pgstat_backend.c
@@ -36,7 +36,7 @@
* reported within critical sections so we use static memory in order to avoid
* memory allocation.
*/
-static PgStat_BackendPending PendingBackendStats;
+PgStat_BackendPending PendingBackendStats;
static bool backend_has_iostats = false;
/*
@@ -47,6 +47,11 @@ static bool backend_has_iostats = false;
*/
static WalUsage prevBackendWalUsage;
+/*
+ * For backend commit and rollback statistics.
+ */
+bool backend_has_xactstats = false;
+
/*
* Utility routines to report I/O stats for backends, kept here to avoid
* exposing PendingBackendStats to the outside world.
@@ -259,6 +264,34 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref)
prevBackendWalUsage = pgWalUsage;
}
+/*
+ * Flush out locally pending backend transaction statistics. Locking is managed
+ * by the caller.
+ */
+static void
+pgstat_flush_backend_entry_xact(PgStat_EntryRef *entry_ref)
+{
+ PgStatShared_Backend *shbackendent;
+
+ /*
+ * This function can be called even if nothing at all has happened for
+ * transaction statistics. In this case, avoid unnecessarily modifying
+ * the stats entry.
+ */
+ if (!backend_has_xactstats)
+ return;
+
+ shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
+
+ shbackendent->stats.xact_commit += PendingBackendStats.pending_xact_commit;
+ shbackendent->stats.xact_rollback += PendingBackendStats.pending_xact_rollback;
+
+ PendingBackendStats.pending_xact_commit = 0;
+ PendingBackendStats.pending_xact_rollback = 0;
+
+ backend_has_xactstats = false;
+}
+
/*
* Flush out locally pending backend statistics
*
@@ -283,6 +316,10 @@ pgstat_flush_backend(bool nowait, bits32 flags)
pgstat_backend_wal_have_pending())
has_pending_data = true;
+ /* Some transaction data pending? */
+ if ((flags & PGSTAT_BACKEND_FLUSH_XACT) && backend_has_xactstats)
+ has_pending_data = true;
+
if (!has_pending_data)
return false;
@@ -298,6 +335,9 @@ pgstat_flush_backend(bool nowait, bits32 flags)
if (flags & PGSTAT_BACKEND_FLUSH_WAL)
pgstat_flush_backend_entry_wal(entry_ref);
+ if (flags & PGSTAT_BACKEND_FLUSH_XACT)
+ pgstat_flush_backend_entry_xact(entry_ref);
+
pgstat_unlock_entry(entry_ref);
return false;
diff --git a/src/backend/utils/activity/pgstat_database.c b/src/backend/utils/activity/pgstat_database.c
index b31f20d41bc..400a8c5d734 100644
--- a/src/backend/utils/activity/pgstat_database.c
+++ b/src/backend/utils/activity/pgstat_database.c
@@ -342,6 +342,13 @@ pgstat_update_dbstats(TimestampTz ts)
dbentry->blk_read_time += pgStatBlockReadTime;
dbentry->blk_write_time += pgStatBlockWriteTime;
+ /* Do the same for backend stats */
+ PendingBackendStats.pending_xact_commit += pgStatXactCommit;
+ PendingBackendStats.pending_xact_rollback += pgStatXactRollback;
+
+ backend_has_xactstats = true;
+ pgstat_report_fixed = true;
+
if (pgstat_should_report_connstat())
{
long secs;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 202bd2d5ace..0fdbaf79780 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -490,6 +490,8 @@ typedef struct PgStat_Backend
TimestampTz stat_reset_timestamp;
PgStat_BktypeIO io_stats;
PgStat_WalCounters wal_counters;
+ PgStat_Counter xact_commit;
+ PgStat_Counter xact_rollback;
} PgStat_Backend;
/* ---------
@@ -502,6 +504,12 @@ typedef struct PgStat_BackendPending
* Backend statistics store the same amount of IO data as PGSTAT_KIND_IO.
*/
PgStat_PendingIO pending_io;
+
+ /*
+ * Transaction statistics pending flush.
+ */
+ PgStat_Counter pending_xact_commit;
+ PgStat_Counter pending_xact_rollback;
} PgStat_BackendPending;
/*
@@ -801,6 +809,13 @@ extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
+/*
+ * Variables in pgstat_backend.c
+ */
+
+extern PGDLLIMPORT PgStat_BackendPending PendingBackendStats;
+extern PGDLLIMPORT bool backend_has_xactstats;
+
/*
* Variables in pgstat_bgwriter.c
*/
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 6cf00008f63..b97184c6539 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -616,7 +616,8 @@ extern void pgstat_archiver_snapshot_cb(void);
/* flags for pgstat_flush_backend() */
#define PGSTAT_BACKEND_FLUSH_IO (1 << 0) /* Flush I/O statistics */
#define PGSTAT_BACKEND_FLUSH_WAL (1 << 1) /* Flush WAL statistics */
-#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL)
+#define PGSTAT_BACKEND_FLUSH_XACT (1 << 2) /* Flush xact statistics */
+#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_XACT)
extern bool pgstat_flush_backend(bool nowait, bits32 flags);
extern bool pgstat_backend_flush_cb(bool nowait);
--
2.34.1
--jg9kqX3osLGO+8A7
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v4-0002-Adding-XID-generation-count-per-backend.patch"
^ permalink raw reply [nested|flat] 248+ messages in thread
* Adding per backend commit and rollback counters
@ 2025-08-04 14:20 Bertrand Drouvot <[email protected]>
2025-08-07 08:17 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
0 siblings, 1 reply; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-04 14:20 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>
Hi hackers,
PFA a patch for $SUBJECT.
Currently we can find xact_commit and xact_rollback in pg_stat_database but we
don't have this information per backend.
This patch adds 2 functions: pg_stat_get_backend_xact_commit() and
pg_stat_get_backend_xact_rollback() to report the number of transactions that
have been committed/rolled back for a given backend PID.
I think having this information per-backend could be useful, for example, to:
- check which application is producing the highest number of commit / rollback
- check if the application's hosts have "uniform" commit/rollback pattern
- check if some application's hosts are doing a lot of rollback (as compared
to the other hosts): that could mean those hosts are not using an up-to-date
application version
This patch is pretty straightforward as it relies on the existing per backend
statistics machinery that has been added in 9aea73fc61d (so that there is not
that much design to discuss).
On a side note, I noticed that when a transaction fails, say this way:
postgres=# insert into bdt2 values(1);
ERROR: relation "bdt2" does not exist
Then the existing pg_stat_get_db_xact_rollback() does not return the rollback
increment (so does pg_stat_database.xact_rollback). Indeed, the flush is done
during the next commit or explicit rollback.
Maybe we could add an extra counter, that tracks the transactions that have not
been explicitly rolled back (xact_error or such) and flush it at the right time.
Looking forward to your feedback,
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
^ permalink raw reply [nested|flat] 248+ messages in thread
* Re: Adding per backend commit and rollback counters
2025-08-04 14:20 Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
@ 2025-08-07 08:17 ` Bertrand Drouvot <[email protected]>
2025-08-10 07:47 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
0 siblings, 1 reply; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-07 08:17 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>
Hi,
On Mon, Aug 04, 2025 at 02:20:48PM +0000, Bertrand Drouvot wrote:
> This patch is pretty straightforward as it relies on the existing per backend
> statistics machinery that has been added in 9aea73fc61d (so that there is not
> that much design to discuss).
Still, while working on adding more backend stats (more on that later), I
realized that in v1, I missed to use pgstat_report_fixed (recently added in
793928c2d5a): the attached fixes that.
Also, I think it's better to put the new xact pending counters in the existing
PgStat_BackendPending, done that way in the attached.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
^ permalink raw reply [nested|flat] 248+ messages in thread
* Re: Adding per backend commit and rollback counters
2025-08-04 14:20 Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-07 08:17 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
@ 2025-08-10 07:47 ` Bertrand Drouvot <[email protected]>
2025-08-28 16:07 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
0 siblings, 1 reply; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-10 07:47 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>
Hi,
On Thu, Aug 07, 2025 at 08:17:26AM +0000, Bertrand Drouvot wrote:
> Hi,
>
> On Mon, Aug 04, 2025 at 02:20:48PM +0000, Bertrand Drouvot wrote:
> > This patch is pretty straightforward as it relies on the existing per backend
> > statistics machinery that has been added in 9aea73fc61d (so that there is not
> > that much design to discuss).
>
> Still, while working on adding more backend stats (more on that later), I
> realized that in v1, I missed to use pgstat_report_fixed (recently added in
> 793928c2d5a): the attached fixes that.
>
> Also, I think it's better to put the new xact pending counters in the existing
> PgStat_BackendPending, done that way in the attached.
Another metric that could be useful is to track the XIDs generated by backend.
That would help to see if a backend is consuming XIDs at a high rate.
We can not rely on the number of commits or rollbacks as they take into account
the virtual transactions.
So a new counter has been added in 0002 attached. Also, v3 changes the way
the statistics are displayed. I've in mind to add much more statistics per backend
(such a number of seqscans, vacuum count, analyze count..., I'll open a dedicated
thread for those) and I think that a single view to display them all makes
more sense than a lot of individual functions. This view is added in 0003.
To sum up, v3 contains:
0001 -
Adding per backend commit and rollback counters
It relies on the existing per backend statistics that has been added in
9aea73fc61d. A new function is called in AtEOXact_PgStat() to increment those
two new counters.
0002 -
Adding XID generation count per backend
This patch adds a new counter to record the number of XIDs generated per
backend. It will help to detect if a backend is consuming XIDs at a high rate.
Virtual transactions are not taken into account on purpose, we do want to track
only the XID where there is a risk of wraparound.
The counter is not part of PgStat_BackendPending, because we want to avoid
an extra function call in this code path to increment the counter in
PendingBackendStats. The counter increment here behaves more or less the same as
we do for WAL statistics.
0003 -
Adding the pg_stat_backend view
This view displays one row per server process, showing statistics related to
the current activity of that process. It currently displays the pid, the
number of XIDs generated, the number of commits, the number of rollbacks and the
time at which these statistics were last reset.
It's built on top of a new function (pg_stat_get_backend_statistics()). The idea
is the same as pg_stat_activity and pg_stat_get_activity().
Adding documentation and tests.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
^ permalink raw reply [nested|flat] 248+ messages in thread
* Re: Adding per backend commit and rollback counters
2025-08-04 14:20 Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-07 08:17 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-10 07:47 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
@ 2025-08-28 16:07 ` Bertrand Drouvot <[email protected]>
2026-03-30 20:19 ` Re: Adding per backend commit and rollback counters Kuba Knysiak <[email protected]>
0 siblings, 1 reply; 248+ messages in thread
From: Bertrand Drouvot @ 2025-08-28 16:07 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>
Hi,
On Sun, Aug 10, 2025 at 07:47:09AM +0000, Bertrand Drouvot wrote:
> To sum up, v3 contains:
>
> 0001 -
> Adding per backend commit and rollback counters
> 0002 -
> Adding XID generation count per backend
> 0003 -
> Adding the pg_stat_backend view
Following recent conversations in [1], those changes have been made in v4
attached:
- avoid tracking the commit and rollback counters twice (for databases and for
backends) but increment the backend stats when the database ones are flushed. Same
idea as [2].
- pg_stat_backend is too generic (see [3]), let's use pg_stat_backend_transaction
instead. I deliberately did not use pg_stat_backend_xact to not confuse with the
other "*xact*" functions/views where the meaning is not the same. I'm open to
other naming suggestion though.
[1]: https://www.postgresql.org/message-id/flat/aJrxug4LCg4Hm5Mm%40ip-10-97-1-34.eu-west-3.compute.intern...
[2]: https://www.postgresql.org/message-id/7fhpds4xqk6bnudzmzkqi33pinsxammpljwde5gfkjdygvejrj%40ojkzfr7dx...
[3]: https://www.postgresql.org/message-id/aK8OuVPmmDTc9CFX%40ip-10-97-1-34.eu-west-3.compute.internal
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
^ permalink raw reply [nested|flat] 248+ messages in thread
* Re: Adding per backend commit and rollback counters
2025-08-04 14:20 Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-07 08:17 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-10 07:47 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-28 16:07 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
@ 2026-03-30 20:19 ` Kuba Knysiak <[email protected]>
2026-03-31 09:24 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
0 siblings, 1 reply; 248+ messages in thread
From: Kuba Knysiak @ 2026-03-30 20:19 UTC (permalink / raw)
To: [email protected]; +Cc: Bertrand Drouvot <[email protected]>
Hello,
after reviewing the patch together with Miłosz, we found the following:
- In pgstatfuncs.c, we call pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL) for each backend row. That path acquires ProcArrayLock via BackendPidGetProc(), so this repeats lock acquisition for every row. We could simplify this and avoid taking the lock altogether by fetching directly with pgstat_fetch_stat_backend(local_beentry->proc_number).
Also, shouldn't this patch bump catversion?
Regards,
Kuba
The new status of this patch is: Waiting on Author
^ permalink raw reply [nested|flat] 248+ messages in thread
* Re: Adding per backend commit and rollback counters
2025-08-04 14:20 Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-07 08:17 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-10 07:47 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-28 16:07 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2026-03-30 20:19 ` Re: Adding per backend commit and rollback counters Kuba Knysiak <[email protected]>
@ 2026-03-31 09:24 ` Bertrand Drouvot <[email protected]>
2026-07-06 11:41 ` Re: Adding per backend commit and rollback counters Nishant Sharma <[email protected]>
0 siblings, 1 reply; 248+ messages in thread
From: Bertrand Drouvot @ 2026-03-31 09:24 UTC (permalink / raw)
To: Kuba Knysiak <[email protected]>; +Cc: [email protected]
Hi,
On Mon, Mar 30, 2026 at 08:19:13PM +0000, Kuba Knysiak wrote:
> Hello,
> after reviewing the patch together with Miłosz, we found the following:
Thanks for the review!
> - In pgstatfuncs.c, we call pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL)
> for each backend row. That path acquires ProcArrayLock via BackendPidGetProc(),
> so this repeats lock acquisition for every row. We could simplify this and avoid
> taking the lock altogether by fetching directly with
> pgstat_fetch_stat_backend(local_beentry->proc_number).
Yeah, I think that's a good point. Done that way in the attached. Also adding a
check on the backend type as it was done in pgstat_fetch_stat_backend_by_pid().
> Also, shouldn't this patch bump catversion?
Yes and that was mentioned in the 0003 commit message. We usually don't change
it in the patch itself (could easily produce rebase noise) but just put an
XXX in the commit message so that it's not forgoten when pushed.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
^ permalink raw reply [nested|flat] 248+ messages in thread
* Re: Adding per backend commit and rollback counters
2025-08-04 14:20 Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-07 08:17 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-10 07:47 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-28 16:07 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2026-03-30 20:19 ` Re: Adding per backend commit and rollback counters Kuba Knysiak <[email protected]>
2026-03-31 09:24 ` Re: Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
@ 2026-07-06 11:41 ` Nishant Sharma <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Nishant Sharma @ 2026-07-06 11:41 UTC (permalink / raw)
To: Bertrand Drouvot <[email protected]>; +Cc: Kuba Knysiak <[email protected]>; [email protected]
Thanks for the v5 patch set!
Here are my review comments:
1) Patches need re-base. Not able to apply.
2) PGSTAT_BACKEND_FLUSH_XACT collision with newly committed
PGSTAT_BACKEND_FLUSH_LOCK.
3) What if pgStatXactCommit and pgStatXactRollback are 0? We unnecessarily
make backend_has_xactstats as true while updating the pending struct
values. In this process unnecessary ref_lock would be taken and
stats.xact_commit, stats.xact_rollback would be updated with 0 and then
ref_lock is unlocked.
4) PendingBackendStats was static but it was removed in this change, yet
the comment above still mentions it. Also it is killing the purpose of
"Utility routines to report I/O stats for backends ..." comment mentioned
in pgstat_backend.c. It appears the existing helper I/O routines' purpose
is eliminated. This doesn't look good.
4) I don't see any function using plural form like
pg_stat_get_backend_transactions in pg_proc.dat
5) The thread started with only commit and rollback counters, but xid was
added in v3, along with the idea of adding more, such as "seqscans, vacuum
count, analyze count...". This makes me curious: why can't these other
counters be added in this same thread? If these others aren't added now,
why was xid added? I suggest this thread should only include commit and
rollback counters, and xid should be added with the other metrics in a new
thread.
Regards,
Nishant Sharma,
EDB, Pune.
https://www.enterprisedb.com/
^ permalink raw reply [nested|flat] 248+ messages in thread
* [PATCH] Introduce an option to make logical replication database specific.
@ 2026-04-04 15:16 Antonin Houska <[email protected]>
0 siblings, 0 replies; 248+ messages in thread
From: Antonin Houska @ 2026-04-04 15:16 UTC (permalink / raw)
By default, the logical decoding assumes access to shared catalogs, so the
snapshot builder needs to consider cluster-wide XIDs during startup. That in
turn means that, if any transaction is already running (and has XID assigned),
the snapshot builder needs to wait for its completion, as it does not know if
that transaction performed catalog changes earlier.
Possible problem with this concept is that if REPACK (CONCURRENTLY) is running
in some database, backends running the same command in other databases get
stuck until the first one has committed. Thus only as single backend in the
cluster can run REPACK (CONCURRENTLY) at any time. Likewise, REPACK
(CONCURRENTLY) can block walsenders starting on behalf of subscriptions
throughout the cluster.
This patch adds a new option to logical replication output plugin, to declare
that it does not use shared catalogs (i.e. catalogs that can be changed by
transactions running in other databases in the cluster). In that case, no
snapshot the backend will use during the decoding needs to contain information
about transactions running in other databases. Thus the snapshot builder only
needs to wait for completion of transactions in the current database.
Currently we only use this option in the REPACK background worker. It could
possibly be used in the plugin for logical replication too, however that would
need thorough analysis of that plugin.
The patch bumps WAL version number, due to a new field in xl_running_xacts.
---
contrib/pg_visibility/pg_visibility.c | 4 +-
doc/src/sgml/logicaldecoding.sgml | 4 ++
src/backend/access/index/genam.c | 18 +++++++
src/backend/access/rmgrdesc/standbydesc.c | 2 +
src/backend/access/transam/xlog.c | 2 +-
src/backend/access/transam/xlogfuncs.c | 2 +-
src/backend/postmaster/bgwriter.c | 2 +-
src/backend/replication/logical/decode.c | 8 ++-
src/backend/replication/logical/logical.c | 5 ++
src/backend/replication/logical/snapbuild.c | 52 ++++++++++++++++---
.../pgoutput_repack/pgoutput_repack.c | 7 +++
src/backend/replication/slot.c | 2 +-
src/backend/storage/ipc/procarray.c | 23 +++++++-
src/backend/storage/ipc/standby.c | 14 ++++-
src/include/access/genam.h | 8 +++
src/include/access/xlog_internal.h | 2 +-
src/include/replication/output_plugin.h | 1 +
src/include/replication/snapbuild.h | 3 +-
src/include/storage/procarray.h | 2 +-
src/include/storage/standby.h | 3 +-
src/include/storage/standbydefs.h | 1 +
21 files changed, 144 insertions(+), 21 deletions(-)
diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c
index dfab0b64cf5..d564bd2a00c 100644
--- a/contrib/pg_visibility/pg_visibility.c
+++ b/contrib/pg_visibility/pg_visibility.c
@@ -621,7 +621,7 @@ GetStrictOldestNonRemovableTransactionId(Relation rel)
else if (rel == NULL || rel->rd_rel->relisshared)
{
/* Shared relation: take into account all running xids */
- runningTransactions = GetRunningTransactionData();
+ runningTransactions = GetRunningTransactionData(InvalidOid);
LWLockRelease(ProcArrayLock);
LWLockRelease(XidGenLock);
return runningTransactions->oldestRunningXid;
@@ -632,7 +632,7 @@ GetStrictOldestNonRemovableTransactionId(Relation rel)
* Normal relation: take into account xids running within the current
* database
*/
- runningTransactions = GetRunningTransactionData();
+ runningTransactions = GetRunningTransactionData(InvalidOid);
LWLockRelease(ProcArrayLock);
LWLockRelease(XidGenLock);
return runningTransactions->oldestDatabaseRunningXid;
diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml
index 6dc49108997..28089d1053c 100644
--- a/doc/src/sgml/logicaldecoding.sgml
+++ b/doc/src/sgml/logicaldecoding.sgml
@@ -959,6 +959,7 @@ typedef struct OutputPluginOptions
{
OutputPluginOutputType output_type;
bool receive_rewrites;
+ bool need_shared_catalogs;
} OutputPluginOptions;
</programlisting>
<literal>output_type</literal> has to either be set to
@@ -969,6 +970,9 @@ typedef struct OutputPluginOptions
also be called for changes made by heap rewrites during certain DDL
operations. These are of interest to plugins that handle DDL
replication, but they require special handling.
+ <literal>need_shared_catalogs</literal> can be set to false if you are
+ sure the plugin functions do not access shared system catalogs. It can
+ speed up creation of replication slots that use this plugin.
</para>
<para>
diff --git a/src/backend/access/index/genam.c b/src/backend/access/index/genam.c
index 1408989c568..df092dc999a 100644
--- a/src/backend/access/index/genam.c
+++ b/src/backend/access/index/genam.c
@@ -37,6 +37,14 @@
#include "utils/ruleutils.h"
#include "utils/snapmgr.h"
+/*
+ * If a backend is going to do logical decoding and if the output plugin does
+ * not need to access shared catalogs, setting this variable to false can make
+ * the decoding startup faster. In particular, the backend will not need to
+ * wait for completion of already running transactions in other databases.
+ */
+bool accessSharedCatalogsInDecoding = true;
+
/* ----------------------------------------------------------------
* general access method routines
@@ -394,6 +402,16 @@ systable_beginscan(Relation heapRelation,
SysScanDesc sysscan;
Relation irel;
+ /*
+ * If this backend promised that it won't access shared catalogs during
+ * logical decoding, this seems to be the right place to check.
+ *
+ * XXX Should this be ereport(ERROR) ?
+ */
+ Assert(!HistoricSnapshotActive() ||
+ accessSharedCatalogsInDecoding ||
+ !heapRelation->rd_rel->relisshared);
+
if (indexOK &&
!IgnoreSystemIndexes &&
!ReindexIsProcessingIndex(indexId))
diff --git a/src/backend/access/rmgrdesc/standbydesc.c b/src/backend/access/rmgrdesc/standbydesc.c
index 0a291354ae2..685d1bdb024 100644
--- a/src/backend/access/rmgrdesc/standbydesc.c
+++ b/src/backend/access/rmgrdesc/standbydesc.c
@@ -41,6 +41,8 @@ standby_desc_running_xacts(StringInfo buf, xl_running_xacts *xlrec)
for (i = 0; i < xlrec->subxcnt; i++)
appendStringInfo(buf, " %u", xlrec->xids[xlrec->xcnt + i]);
}
+
+ appendStringInfo(buf, "; dbid: %u", xlrec->dbid);
}
void
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 9e8999bbb61..1a6c1456d2c 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7731,7 +7731,7 @@ CreateCheckPoint(int flags)
* recovery we don't need to write running xact data.
*/
if (!shutdown && XLogStandbyInfoActive())
- LogStandbySnapshot();
+ LogStandbySnapshot(InvalidOid);
START_CRIT_SECTION();
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 65bbaeda59c..0f5979691e6 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -245,7 +245,7 @@ pg_log_standby_snapshot(PG_FUNCTION_ARGS)
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("pg_log_standby_snapshot() can only be used if \"wal_level\" >= \"replica\"")));
- recptr = LogStandbySnapshot();
+ recptr = LogStandbySnapshot(InvalidOid);
/*
* As a convenience, return the WAL location of the last inserted record
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1d8947774a9..a30de4262eb 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -289,7 +289,7 @@ BackgroundWriterMain(const void *startup_data, size_t startup_data_len)
if (now >= timeout &&
last_snapshot_lsn <= GetLastImportantRecPtr())
{
- last_snapshot_lsn = LogStandbySnapshot();
+ last_snapshot_lsn = LogStandbySnapshot(InvalidOid);
last_snapshot_ts = now;
}
}
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index 2be5d8d4bd9..1353d004aac 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -382,7 +382,13 @@ standby_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
{
xl_running_xacts *running = (xl_running_xacts *) XLogRecGetData(r);
- SnapBuildProcessRunningXacts(builder, buf->origptr, running);
+
+ /*
+ * If the plugin does not access shared catalogs, only keep
+ * track of transactions in the current database.
+ */
+ SnapBuildProcessRunningXacts(builder, buf->origptr, running,
+ !ctx->options.need_shared_catalogs);
/*
* Abort all transactions that we keep track of, that are
diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c
index f20a0fe70ad..89043a03497 100644
--- a/src/backend/replication/logical/logical.c
+++ b/src/backend/replication/logical/logical.c
@@ -289,6 +289,11 @@ StartupDecodingContext(List *output_plugin_options,
ctx->write = do_write;
ctx->update_progress = update_progress;
+ /*
+ * Assume true for safety, the startup callback can change that.
+ */
+ ctx->options.need_shared_catalogs = true;
+
ctx->output_plugin_options = output_plugin_options;
ctx->fast_forward = fast_forward;
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index b4269a3b102..054a7b16f43 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -125,6 +125,7 @@
#include <sys/stat.h>
#include <unistd.h>
+#include "access/genam.h"
#include "access/heapam_xlog.h"
#include "access/transam.h"
#include "access/xact.h"
@@ -170,7 +171,8 @@ static inline bool SnapBuildXidHasCatalogChanges(SnapBuild *builder, Transaction
uint32 xinfo);
/* xlog reading helper functions for SnapBuildProcessRunningXacts */
-static bool SnapBuildFindSnapshot(SnapBuild *builder, XLogRecPtr lsn, xl_running_xacts *running);
+static bool SnapBuildFindSnapshot(SnapBuild *builder, XLogRecPtr lsn,
+ xl_running_xacts *running, bool db_specific);
static void SnapBuildWaitSnapshot(xl_running_xacts *running, TransactionId cutoff);
/* serialization functions */
@@ -1136,7 +1138,8 @@ SnapBuildXidHasCatalogChanges(SnapBuild *builder, TransactionId xid,
* anymore.
*/
void
-SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn, xl_running_xacts *running)
+SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn, xl_running_xacts *running,
+ bool db_specific)
{
ReorderBufferTXN *txn;
TransactionId xmin;
@@ -1149,7 +1152,7 @@ SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn, xl_running_xact
if (builder->state < SNAPBUILD_CONSISTENT)
{
/* returns false if there's no point in performing cleanup just yet */
- if (!SnapBuildFindSnapshot(builder, lsn, running))
+ if (!SnapBuildFindSnapshot(builder, lsn, running, db_specific))
return;
}
else
@@ -1166,8 +1169,13 @@ SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn, xl_running_xact
* (see SnapBuildCommitTxn). Because of this, xmax can be lower than
* xmin, which looks odd but is correct and actually more efficient, since
* we hit fast paths in heapam_visibility.c.
+ *
+ * If database specific transaction info was used during startup, the info
+ * for the whole cluster can make xmin go backwards. That would be bad
+ * because we might no longer have older XIDs in ->committed.
*/
- builder->xmin = running->oldestRunningXid;
+ if (NormalTransactionIdFollows(running->oldestRunningXid, builder->xmin))
+ builder->xmin = running->oldestRunningXid;
/* Remove transactions we don't need to keep track off anymore */
SnapBuildPurgeOlderTxn(builder);
@@ -1182,7 +1190,10 @@ SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn, xl_running_xact
* the record we're reading now.
*/
xmin = ReorderBufferGetOldestXmin(builder->reorder);
- if (xmin == InvalidTransactionId)
+ /*
+ * Like above, do not let slot xmin go backwards.
+ */
+ if (xmin == InvalidTransactionId && !db_specific)
xmin = running->oldestRunningXid;
elog(DEBUG3, "xmin: %u, xmax: %u, oldest running: %u, oldest xmin: %u",
builder->xmin, builder->xmax, running->oldestRunningXid, xmin);
@@ -1238,7 +1249,8 @@ SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn, xl_running_xact
* using the xl_running_xacts record.
*/
static bool
-SnapBuildFindSnapshot(SnapBuild *builder, XLogRecPtr lsn, xl_running_xacts *running)
+SnapBuildFindSnapshot(SnapBuild *builder, XLogRecPtr lsn, xl_running_xacts *running,
+ bool db_specific)
{
/* ---
* Build catalog decoding snapshot incrementally using information about
@@ -1265,6 +1277,28 @@ SnapBuildFindSnapshot(SnapBuild *builder, XLogRecPtr lsn, xl_running_xacts *runn
* ---
*/
+ if (db_specific)
+ {
+ /*
+ * If we should only keep track of transactions running in the current
+ * database, we need transaction info from exactly that
+ * database. Invalid 'dbid' (all databases) would satisfy our needs
+ * too, but it could make us wait unnecessarily for completion of
+ * transactions running in other databases.
+ */
+ if (running->dbid != MyDatabaseId)
+ {
+ LogStandbySnapshot(MyDatabaseId);
+ return false;
+ }
+
+ /*
+ * We'd better be able to check during scan if the plugin does not
+ * lie.
+ */
+ accessSharedCatalogsInDecoding = false;
+ }
+
/*
* xl_running_xacts record is older than what we can use, we might not
* have all necessary catalog rows anymore.
@@ -1465,7 +1499,11 @@ SnapBuildWaitSnapshot(xl_running_xacts *running, TransactionId cutoff)
*/
if (!RecoveryInProgress())
{
- LogStandbySnapshot();
+ /*
+ * If the last transaction info was about specific database, so needs
+ * to be the next one - at least until we're in the CONSISTENT state.
+ */
+ LogStandbySnapshot(running->dbid);
}
}
diff --git a/src/backend/replication/pgoutput_repack/pgoutput_repack.c b/src/backend/replication/pgoutput_repack/pgoutput_repack.c
index 221260ca0a8..bb3a880a4c3 100644
--- a/src/backend/replication/pgoutput_repack/pgoutput_repack.c
+++ b/src/backend/replication/pgoutput_repack/pgoutput_repack.c
@@ -52,6 +52,13 @@ repack_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
/* Probably unnecessary, as we don't use the SQL interface ... */
opt->output_type = OUTPUT_PLUGIN_BINARY_OUTPUT;
+ /*
+ * By declaring that our output plugin does not need shared catalogs, we
+ * avoid waiting for completion of transactions running in other databases
+ * than the one we're connected to.
+ */
+ opt->need_shared_catalogs = false;
+
if (ctx->output_plugin_options != NIL)
{
ereport(ERROR,
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index a9092fc2382..9533515a63b 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -1762,7 +1762,7 @@ ReplicationSlotReserveWal(void)
XLogRecPtr flushptr;
/* make sure we have enough information to start */
- flushptr = LogStandbySnapshot();
+ flushptr = LogStandbySnapshot(InvalidOid);
/* and make sure it's fsynced to disk */
XLogFlush(flushptr);
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index cc207cb56e3..92ed34128e5 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -2631,9 +2631,11 @@ ProcArrayInstallRestoredXmin(TransactionId xmin, PGPROC *proc)
*
* Note that if any transaction has overflowed its cached subtransactions
* then there is no real need include any subtransactions.
+ *
+ * If 'dbid' is valid, only gather transactions running in that database.
*/
RunningTransactions
-GetRunningTransactionData(void)
+GetRunningTransactionData(Oid dbid)
{
/* result workspace */
static RunningTransactionsData CurrentRunningXactsData;
@@ -2708,6 +2710,18 @@ GetRunningTransactionData(void)
if (!TransactionIdIsValid(xid))
continue;
+ /*
+ * Filter by database OID if requested.
+ */
+ if (OidIsValid(dbid))
+ {
+ int pgprocno = arrayP->pgprocnos[index];
+ PGPROC *proc = &allProcs[pgprocno];
+
+ if (proc->databaseId != dbid)
+ continue;
+ }
+
/*
* Be careful not to exclude any xids before calculating the values of
* oldestRunningXid and suboverflowed, since these are used to clean
@@ -2758,6 +2772,12 @@ GetRunningTransactionData(void)
PGPROC *proc = &allProcs[pgprocno];
int nsubxids;
+ /*
+ * Filter by database OID if requested.
+ */
+ if (OidIsValid(dbid) && proc->databaseId != dbid)
+ continue;
+
/*
* Save subtransaction XIDs. Other backends can't add or remove
* entries while we're holding XidGenLock.
@@ -2791,6 +2811,7 @@ GetRunningTransactionData(void)
* increases if slots do.
*/
+ CurrentRunningXacts->dbid = dbid;
CurrentRunningXacts->xcnt = count - subcount;
CurrentRunningXacts->subxcnt = subcount;
CurrentRunningXacts->subxid_status = suboverflowed ? SUBXIDS_IN_SUBTRANS : SUBXIDS_IN_ARRAY;
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index de9092fdf5b..c653ea742bc 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -1188,6 +1188,14 @@ standby_redo(XLogReaderState *record)
xl_running_xacts *xlrec = (xl_running_xacts *) XLogRecGetData(record);
RunningTransactionsData running;
+ /*
+ * Records issued for specific database are not suitable for physical
+ * replication because that affects the whole cluster. In particular,
+ * the list of XID is probably incomplete here.
+ */
+ if (OidIsValid(xlrec->dbid))
+ return;
+
running.xcnt = xlrec->xcnt;
running.subxcnt = xlrec->subxcnt;
running.subxid_status = xlrec->subxid_overflow ? SUBXIDS_MISSING : SUBXIDS_IN_ARRAY;
@@ -1277,11 +1285,12 @@ standby_redo(XLogReaderState *record)
* as there's no independent knob to just enable logical decoding. For
* details of how this is used, check snapbuild.c's introductory comment.
*
+ * If 'dbid' is valid, only gather transactions running in that database.
*
* Returns the RecPtr of the last inserted record.
*/
XLogRecPtr
-LogStandbySnapshot(void)
+LogStandbySnapshot(Oid dbid)
{
XLogRecPtr recptr;
RunningTransactions running;
@@ -1314,7 +1323,7 @@ LogStandbySnapshot(void)
* Log details of all in-progress transactions. This should be the last
* record we write, because standby will open up when it sees this.
*/
- running = GetRunningTransactionData();
+ running = GetRunningTransactionData(dbid);
/*
* GetRunningTransactionData() acquired ProcArrayLock, we must release it.
@@ -1358,6 +1367,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts)
xl_running_xacts xlrec;
XLogRecPtr recptr;
+ xlrec.dbid = CurrRunningXacts->dbid;
xlrec.xcnt = CurrRunningXacts->xcnt;
xlrec.subxcnt = CurrRunningXacts->subxcnt;
xlrec.subxid_overflow = (CurrRunningXacts->subxid_status != SUBXIDS_IN_ARRAY);
diff --git a/src/include/access/genam.h b/src/include/access/genam.h
index b69320a7fc8..56c573399ab 100644
--- a/src/include/access/genam.h
+++ b/src/include/access/genam.h
@@ -136,6 +136,14 @@ typedef struct IndexOrderByDistance
bool isnull;
} IndexOrderByDistance;
+/*
+ * Is the backend interested in shared catalogs when performing logical
+ * decoding?
+ *
+ * XXX Is there a better place for this declaration?
+ */
+extern bool accessSharedCatalogsInDecoding;
+
/*
* generalized index_ interface routines (in indexam.c)
*/
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index 10c18d39ff8..13ae3ad4fbb 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -32,7 +32,7 @@
/*
* Each page of XLOG file has a header like this:
*/
-#define XLOG_PAGE_MAGIC 0xD11E /* can be used as WAL version indicator */
+#define XLOG_PAGE_MAGIC 0xD11F /* can be used as WAL version indicator */
typedef struct XLogPageHeaderData
{
diff --git a/src/include/replication/output_plugin.h b/src/include/replication/output_plugin.h
index 842fcde67f9..917f3cff232 100644
--- a/src/include/replication/output_plugin.h
+++ b/src/include/replication/output_plugin.h
@@ -27,6 +27,7 @@ typedef struct OutputPluginOptions
{
OutputPluginOutputType output_type;
bool receive_rewrites;
+ bool need_shared_catalogs;
} OutputPluginOptions;
/*
diff --git a/src/include/replication/snapbuild.h b/src/include/replication/snapbuild.h
index ccded021433..82552a97997 100644
--- a/src/include/replication/snapbuild.h
+++ b/src/include/replication/snapbuild.h
@@ -93,7 +93,8 @@ extern void SnapBuildProcessNewCid(SnapBuild *builder, TransactionId xid,
XLogRecPtr lsn,
struct xl_heap_new_cid *xlrec);
extern void SnapBuildProcessRunningXacts(SnapBuild *builder, XLogRecPtr lsn,
- struct xl_running_xacts *running);
+ struct xl_running_xacts *running,
+ bool db_specific);
extern void SnapBuildSerializationPoint(SnapBuild *builder, XLogRecPtr lsn);
extern bool SnapBuildSnapshotExists(XLogRecPtr lsn);
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index abdf021e66e..377b3060b9f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -49,7 +49,7 @@ extern bool ProcArrayInstallImportedXmin(TransactionId xmin,
VirtualTransactionId *sourcevxid);
extern bool ProcArrayInstallRestoredXmin(TransactionId xmin, PGPROC *proc);
-extern RunningTransactions GetRunningTransactionData(void);
+extern RunningTransactions GetRunningTransactionData(Oid dbid);
extern bool TransactionIdIsInProgress(TransactionId xid);
extern TransactionId GetOldestNonRemovableTransactionId(Relation rel);
diff --git a/src/include/storage/standby.h b/src/include/storage/standby.h
index 6a314c693cd..8715c08e94f 100644
--- a/src/include/storage/standby.h
+++ b/src/include/storage/standby.h
@@ -126,6 +126,7 @@ typedef enum
typedef struct RunningTransactionsData
{
+ Oid dbid; /* only track xacts in this database */
int xcnt; /* # of xact ids in xids[] */
int subxcnt; /* # of subxact ids in xids[] */
subxids_array_status subxid_status;
@@ -143,7 +144,7 @@ typedef RunningTransactionsData *RunningTransactions;
extern void LogAccessExclusiveLock(Oid dbOid, Oid relOid);
extern void LogAccessExclusiveLockPrepare(void);
-extern XLogRecPtr LogStandbySnapshot(void);
+extern XLogRecPtr LogStandbySnapshot(Oid dbid);
extern void LogStandbyInvalidations(int nmsgs, SharedInvalidationMessage *msgs,
bool relcacheInitFileInval);
diff --git a/src/include/storage/standbydefs.h b/src/include/storage/standbydefs.h
index 231d251fd51..e75b7078766 100644
--- a/src/include/storage/standbydefs.h
+++ b/src/include/storage/standbydefs.h
@@ -46,6 +46,7 @@ typedef struct xl_standby_locks
*/
typedef struct xl_running_xacts
{
+ Oid dbid; /* only track xacts in this database */
int xcnt; /* # of xact ids in xids[] */
int subxcnt; /* # of subxact ids in xids[] */
bool subxid_overflow; /* snapshot overflowed, subxids missing */
--
2.47.3
--=-=-=--
^ permalink raw reply [nested|flat] 248+ messages in thread
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2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
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2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v3 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v1] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v2] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v5 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 08:14 [PATCH v4 1/3] Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-04 14:20 Adding per backend commit and rollback counters Bertrand Drouvot <[email protected]>
2025-08-07 08:17 ` Bertrand Drouvot <[email protected]>
2025-08-10 07:47 ` Bertrand Drouvot <[email protected]>
2025-08-28 16:07 ` Bertrand Drouvot <[email protected]>
2026-03-30 20:19 ` Kuba Knysiak <[email protected]>
2026-03-31 09:24 ` Bertrand Drouvot <[email protected]>
2026-07-06 11:41 ` Nishant Sharma <[email protected]>
2026-04-04 15:16 [PATCH] Introduce an option to make logical replication database specific. Antonin Houska <[email protected]>
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