From cea5e221c3972d162ddead3f0b7a81cc1555461e Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Mon, 4 Aug 2025 08:14:02 +0000 Subject: [PATCH v3 1/3] 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. --- 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