From 5be3ea4753db28cf0c15da65bd6263e0b9f964a4 Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Mon, 4 Aug 2025 08:14:02 +0000 Subject: [PATCH v2 1/2] Adding per backend relation statistics tracking This commit introduces per backend relation stats tracking and adds a new PgStat_BackendRelPending struct to store the pending statistics. To begin with, this commit adds a new counter numscans to record the number of sequential scans initiated on tables. This commit relies on the existing per backend statistics machinery that has been added in 9aea73fc61d. --- src/backend/utils/activity/pgstat_backend.c | 47 +++++++++++++++++++- src/backend/utils/activity/pgstat_relation.c | 7 +++ src/include/pgstat.h | 14 ++++++ src/include/utils/pgstat_internal.h | 3 +- src/tools/pgindent/typedefs.list | 1 + 5 files changed, 70 insertions(+), 2 deletions(-) 75.4% src/backend/utils/activity/ 7.9% src/include/utils/ 15.3% src/include/ diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c index 8714a85e2d9..0644e999e93 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 relations's related statistics. + */ +bool backend_has_relstats = false; + /* * Utility routines to report I/O stats for backends, kept here to avoid * exposing PendingBackendStats to the outside world. @@ -259,6 +264,39 @@ pgstat_flush_backend_entry_wal(PgStat_EntryRef *entry_ref) prevBackendWalUsage = pgWalUsage; } +/* + * Flush out locally pending backend relations's related statistics. Locking is + * managed by the caller. + */ +static void +pgstat_flush_backend_entry_rel(PgStat_EntryRef *entry_ref) +{ + PgStatShared_Backend *shbackendent; + + /* + * This function can be called even if nothing at all has happened for + * relations's related statistics. In this case, avoid unnecessarily + * modifying the stats entry. + */ + if (!backend_has_relstats) + return; + + shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats; + +#define BACKENDREL_ACC(stat) \ + (shbackendent->stats.stat += PendingBackendStats.pending_backendrel.stat) + + BACKENDREL_ACC(heap_scan); +#undef BACKENDREL_ACC + + /* + * Clear out the statistics buffer, so it can be re-used. + */ + MemSet(&PendingBackendStats.pending_backendrel, 0, sizeof(PgStat_BackendRelPending)); + + backend_has_relstats = false; +} + /* * Flush out locally pending backend statistics * @@ -283,6 +321,10 @@ pgstat_flush_backend(bool nowait, bits32 flags) pgstat_backend_wal_have_pending()) has_pending_data = true; + /* Some relations related data pending? */ + if ((flags & PGSTAT_BACKEND_FLUSH_REL) && backend_has_relstats) + has_pending_data = true; + if (!has_pending_data) return false; @@ -298,6 +340,9 @@ 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_REL) + pgstat_flush_backend_entry_rel(entry_ref); + pgstat_unlock_entry(entry_ref); return false; diff --git a/src/backend/utils/activity/pgstat_relation.c b/src/backend/utils/activity/pgstat_relation.c index 69df741cbf6..f2318bddb41 100644 --- a/src/backend/utils/activity/pgstat_relation.c +++ b/src/backend/utils/activity/pgstat_relation.c @@ -898,6 +898,13 @@ pgstat_relation_flush_cb(PgStat_EntryRef *entry_ref, bool nowait) dbentry->blocks_fetched += lstats->counts.blocks_fetched; dbentry->blocks_hit += lstats->counts.blocks_hit; + /* Do the same for backend stats */ + if (lstats->relation && lstats->relation->rd_rel->relkind == RELKIND_RELATION) + PendingBackendStats.pending_backendrel.heap_scan += lstats->counts.numscans; + + backend_has_relstats = true; + pgstat_report_fixed = true; + return true; } diff --git a/src/include/pgstat.h b/src/include/pgstat.h index 202bd2d5ace..fb20cd96bd6 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -490,8 +490,14 @@ typedef struct PgStat_Backend TimestampTz stat_reset_timestamp; PgStat_BktypeIO io_stats; PgStat_WalCounters wal_counters; + PgStat_Counter heap_scan; } PgStat_Backend; +typedef struct PgStat_BackendRelPending +{ + PgStat_Counter heap_scan; +} PgStat_BackendRelPending; + /* --------- * PgStat_BackendPending Non-flushed backend stats. * --------- @@ -502,8 +508,16 @@ typedef struct PgStat_BackendPending * Backend statistics store the same amount of IO data as PGSTAT_KIND_IO. */ PgStat_PendingIO pending_io; + + /* + * Backend statistics related to relations. + */ + PgStat_BackendRelPending pending_backendrel; } PgStat_BackendPending; +extern PgStat_BackendPending PendingBackendStats; +extern bool backend_has_relstats; + /* * Functions in pgstat.c */ diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h index 6cf00008f63..286249c0f3a 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_REL (1 << 2) /* Flush relations related statistics */ +#define PGSTAT_BACKEND_FLUSH_ALL (PGSTAT_BACKEND_FLUSH_IO | PGSTAT_BACKEND_FLUSH_WAL | PGSTAT_BACKEND_FLUSH_REL) extern bool pgstat_flush_backend(bool nowait, bits32 flags); extern bool pgstat_backend_flush_cb(bool nowait); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index a13e8162890..e3f4c71466b 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -2227,6 +2227,7 @@ PgStatShared_Wal PgStat_ArchiverStats PgStat_Backend PgStat_BackendPending +PgStat_BackendRelPending PgStat_BackendSubEntry PgStat_BgWriterStats PgStat_BktypeIO -- 2.34.1