From 9e2f8cb9a87f1d9be91f2f39ef25fbb254944968 Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Mon, 4 Aug 2025 08:14:02 +0000 Subject: [PATCH v1 01/10] 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 (heap_scan) 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/access/heap/heapam.c | 3 ++ src/backend/utils/activity/pgstat_backend.c | 59 +++++++++++++++++++++ src/include/pgstat.h | 14 +++++ src/include/utils/pgstat_internal.h | 3 +- src/tools/pgindent/typedefs.list | 1 + 5 files changed, 79 insertions(+), 1 deletion(-) 73.9% src/backend/utils/activity/ 7.4% src/include/utils/ 15.4% src/include/ 3.2% src/ diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 0dcd6ee817e..d9d6fb6c6ea 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -467,7 +467,10 @@ initscan(HeapScanDesc scan, ScanKey key, bool keep_startblock) * and for sample scans we update stats for tuple fetches). */ if (scan->rs_base.rs_flags & SO_TYPE_SEQSCAN) + { pgstat_count_heap_scan(scan->rs_base.rs_rd); + pgstat_count_backend_rel_heap_scan(); + } } /* diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c index 8714a85e2d9..8797dac68c7 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 relations's related statistics. + */ +static 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; @@ -400,3 +445,17 @@ pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts) { ((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts; } + +#define PGSTAT_COUNT_BACKEND_FUNC(stat) \ +void \ +CppConcat(pgstat_count_backend_rel_,stat)(void) \ +{ \ + if (!pgstat_tracks_backend_bktype(MyBackendType)) \ + return; \ + PendingBackendStats.pending_backendrel.stat++; \ + backend_has_relstats = true; \ + pgstat_report_fixed = true; \ +} + +/* pgstat_count_backend_rel_heap_scan */ +PGSTAT_COUNT_BACKEND_FUNC(heap_scan) diff --git a/src/include/pgstat.h b/src/include/pgstat.h index 202bd2d5ace..7b4dacd27f8 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. * --------- @@ -502,6 +508,11 @@ 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; /* @@ -563,6 +574,9 @@ extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid, extern bool pgstat_tracks_backend_bktype(BackendType bktype); extern void pgstat_create_backend(ProcNumber procnum); +/* used to track backend relations related stats */ +extern void pgstat_count_backend_rel_heap_scan(void); + /* * Functions in pgstat_bgwriter.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 e6f2e93b2d6..61e85da269c 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -2226,6 +2226,7 @@ PgStatShared_Wal PgStat_ArchiverStats PgStat_Backend PgStat_BackendPending +PgStat_BackendRelPending PgStat_BackendSubEntry PgStat_BgWriterStats PgStat_BktypeIO -- 2.34.1