From 5c68c49558f79b9783bf1423af6420680e229770 Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Thu, 13 Aug 2026 12:28:55 +0000 Subject: [PATCH v2 6/6] pgstat: remove PGSTAT_KIND_BACKEND After WAL, Lock, and IO have moved, PGSTAT_KIND_BACKEND contains no data. Remove that kind and pgstat_backend.c together with their build entries, shared structures, callbacks, and call sites. Author: Bertrand Drouvot Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/anCjoFkGah/uB7lw%40bdtpg --- src/backend/utils/activity/Makefile | 1 - src/backend/utils/activity/backend_status.c | 4 - src/backend/utils/activity/meson.build | 1 - src/backend/utils/activity/pgstat.c | 20 --- src/backend/utils/activity/pgstat_backend.c | 179 -------------------- src/include/pgstat.h | 19 --- src/include/utils/pgstat_internal.h | 13 -- src/include/utils/pgstat_kind.h | 15 +- src/test/regress/expected/stats.out | 17 +- src/tools/pgindent/typedefs.list | 2 - 10 files changed, 15 insertions(+), 256 deletions(-) 72.8% src/backend/utils/activity/ 9.8% src/include/utils/ 6.4% src/include/ 10.3% src/test/regress/expected/ diff --git a/src/backend/utils/activity/Makefile b/src/backend/utils/activity/Makefile index 8924b10ed2e..618a04602c8 100644 --- a/src/backend/utils/activity/Makefile +++ b/src/backend/utils/activity/Makefile @@ -20,7 +20,6 @@ OBJS = \ backend_status.o \ pgstat.o \ pgstat_archiver.o \ - pgstat_backend.o \ pgstat_bgwriter.o \ pgstat_checkpointer.o \ pgstat_database.o \ diff --git a/src/backend/utils/activity/backend_status.c b/src/backend/utils/activity/backend_status.c index d685fc5cd87..7088fc09651 100644 --- a/src/backend/utils/activity/backend_status.c +++ b/src/backend/utils/activity/backend_status.c @@ -458,10 +458,6 @@ pgstat_bestart_final(void) PGSTAT_END_WRITE_ACTIVITY(beentry); - /* Create the backend statistics entry */ - if (pgstat_tracks_backend_bktype(MyBackendType)) - pgstat_create_backend(MyProcNumber); - /* Update app name to current GUC setting */ if (application_name) pgstat_report_appname(application_name); diff --git a/src/backend/utils/activity/meson.build b/src/backend/utils/activity/meson.build index 6434c377e53..ea6495b95d3 100644 --- a/src/backend/utils/activity/meson.build +++ b/src/backend/utils/activity/meson.build @@ -5,7 +5,6 @@ backend_sources += files( 'backend_status.c', 'pgstat.c', 'pgstat_archiver.c', - 'pgstat_backend.c', 'pgstat_bgwriter.c', 'pgstat_checkpointer.c', 'pgstat_database.c', diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c index 281104096c3..aad5cef2a3f 100644 --- a/src/backend/utils/activity/pgstat.c +++ b/src/backend/utils/activity/pgstat.c @@ -78,7 +78,6 @@ * * Each statistics kind is handled in a dedicated file: * - pgstat_archiver.c - * - pgstat_backend.c * - pgstat_bgwriter.c * - pgstat_checkpointer.c * - pgstat_database.c @@ -383,21 +382,6 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE] .reset_timestamp_cb = pgstat_subscription_reset_timestamp_cb, }, - [PGSTAT_KIND_BACKEND] = { - .name = "backend", - - .fixed_amount = false, - .write_to_file = false, - - .accessed_across_databases = true, - - .shared_size = sizeof(PgStatShared_Backend), - .shared_data_off = offsetof(PgStatShared_Backend, stats), - .shared_data_len = sizeof(((PgStatShared_Backend *) 0)->stats), - - .reset_timestamp_cb = pgstat_backend_reset_timestamp_cb, - }, - /* stats for fixed-numbered (mostly 1) objects */ [PGSTAT_KIND_ARCHIVER] = { @@ -685,10 +669,6 @@ pgstat_shutdown_hook(int code, Datum arg) Assert(dlist_is_empty(&pgStatPending)); dlist_init(&pgStatPending); - /* drop the backend stats entry */ - if (!pgstat_drop_entry(PGSTAT_KIND_BACKEND, InvalidOid, MyProcNumber, false)) - pgstat_request_entry_refs_gc(); - /* Accumulate per-backend stats into the global stats */ pgstat_wal_acc_backend_cb(); pgstat_lock_acc_backend_cb(); diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c deleted file mode 100644 index b5996d15d8f..00000000000 --- a/src/backend/utils/activity/pgstat_backend.c +++ /dev/null @@ -1,179 +0,0 @@ -/* ------------------------------------------------------------------------- - * - * pgstat_backend.c - * Implementation of backend statistics. - * - * This file contains the implementation of backend statistics. It is kept - * separate from pgstat.c to enforce the line between the statistics access / - * storage implementation and the details about individual types of - * statistics. - * - * This statistics kind uses a proc number as object ID for the hash table - * of pgstats. Entries are created each time a process is spawned, and are - * dropped when the process exits. These are not written to the pgstats file - * on disk. - * - * Copyright (c) 2001-2026, PostgreSQL Global Development Group - * - * IDENTIFICATION - * src/backend/utils/activity/pgstat_backend.c - * ------------------------------------------------------------------------- - */ - -#include "postgres.h" - -#include "storage/proc.h" -#include "storage/procarray.h" -#include "utils/pgstat_internal.h" - -/* - * Returns statistics of a backend by proc number. - */ -PgStat_Backend * -pgstat_fetch_stat_backend(ProcNumber procNumber) -{ - PgStat_Backend *backend_entry; - - backend_entry = (PgStat_Backend *) pgstat_fetch_entry(PGSTAT_KIND_BACKEND, - InvalidOid, procNumber, - NULL); - - return backend_entry; -} - -/* - * Returns statistics of a backend by pid. - * - * This routine includes sanity checks to ensure that the backend exists and - * is running. "bktype" can be optionally defined to return the BackendType - * of the backend whose statistics are returned. - */ -PgStat_Backend * -pgstat_fetch_stat_backend_by_pid(int pid, BackendType *bktype) -{ - PGPROC *proc; - PgBackendStatus *beentry; - ProcNumber procNumber; - PgStat_Backend *backend_stats; - - proc = BackendPidGetProc(pid); - if (bktype) - *bktype = B_INVALID; - - /* this could be an auxiliary process */ - if (!proc) - proc = AuxiliaryPidGetProc(pid); - - if (!proc) - return NULL; - - procNumber = GetNumberFromPGProc(proc); - - beentry = pgstat_get_beentry_by_proc_number(procNumber); - if (!beentry) - return NULL; - - /* check if the backend type tracks statistics */ - if (!pgstat_tracks_backend_bktype(beentry->st_backendType)) - return NULL; - - /* if PID does not match, leave */ - if (beentry->st_procpid != pid) - return NULL; - - if (bktype) - *bktype = beentry->st_backendType; - - /* - * Retrieve the entry. Note that "beentry" may be freed depending on the - * value of stats_fetch_consistency, so do not access it from this point. - */ - backend_stats = pgstat_fetch_stat_backend(procNumber); - if (!backend_stats) - { - if (bktype) - *bktype = B_INVALID; - return NULL; - } - - return backend_stats; -} - -/* - * Create backend statistics entry for proc number. - */ -void -pgstat_create_backend(ProcNumber procnum) -{ - PgStat_EntryRef *entry_ref; - PgStatShared_Backend *shstatent; - - entry_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_BACKEND, InvalidOid, - procnum, false); - shstatent = (PgStatShared_Backend *) entry_ref->shared_stats; - - /* - * NB: need to accept that there might be stats from an older backend, - * e.g. if we previously used this proc number. - */ - memset(&shstatent->stats, 0, sizeof(shstatent->stats)); - pgstat_unlock_entry(entry_ref); -} - -/* - * Backend statistics are not collected for all BackendTypes. - * - * The following BackendTypes do not participate in the backend stats - * subsystem: - * - The same and for the same reasons as in pgstat_tracks_io_bktype(). - * - B_BG_WRITER, B_CHECKPOINTER, B_STARTUP and B_AUTOVAC_LAUNCHER because their - * I/O stats are already visible in pg_stat_io and there is only one of those. - * - * Function returns true if BackendType participates in the backend stats - * subsystem and false if it does not. - * - * When adding a new BackendType, also consider adding relevant restrictions to - * pgstat_tracks_io_object() and pgstat_tracks_io_op(). - */ -bool -pgstat_tracks_backend_bktype(BackendType bktype) -{ - /* - * List every type so that new backend types trigger a warning about - * needing to adjust this switch. - */ - switch (bktype) - { - case B_INVALID: - case B_AUTOVAC_LAUNCHER: - case B_DEAD_END_BACKEND: - case B_ARCHIVER: - case B_LOGGER: - case B_BG_WRITER: - case B_CHECKPOINTER: - case B_IO_WORKER: - case B_STARTUP: - case B_DATACHECKSUMSWORKER_LAUNCHER: - case B_DATACHECKSUMSWORKER_WORKER: - return false; - - case B_AUTOVAC_WORKER: - case B_BACKEND: - case B_BG_WORKER: - case B_STANDALONE_BACKEND: - case B_SLOTSYNC_WORKER: - case B_WAL_RECEIVER: - case B_WAL_SENDER: - case B_WAL_SUMMARIZER: - case B_WAL_WRITER: - return true; - } - - return false; -} - -void -pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts) -{ - ((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts; -} diff --git a/src/include/pgstat.h b/src/include/pgstat.h index cd6bfc9a33b..8282a8413ef 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -534,15 +534,6 @@ typedef struct PgStat_WalStats TimestampTz stat_reset_timestamp; } PgStat_WalStats; -/* ------- - * PgStat_Backend Backend statistics - * ------- - */ -typedef struct PgStat_Backend -{ - TimestampTz stat_reset_timestamp; -} PgStat_Backend; - /* * Functions in pgstat.c */ @@ -579,16 +570,6 @@ extern bool pgstat_have_entry(PgStat_Kind kind, Oid dboid, uint64 objid); extern void pgstat_report_archiver(const char *xlog, bool failed); extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void); -/* - * Functions in pgstat_backend.c - */ - -extern PgStat_Backend *pgstat_fetch_stat_backend(ProcNumber procNumber); -extern PgStat_Backend *pgstat_fetch_stat_backend_by_pid(int pid, - BackendType *bktype); -extern bool pgstat_tracks_backend_bktype(BackendType bktype); -extern void pgstat_create_backend(ProcNumber procnum); - /* * Functions in pgstat_bgwriter.c */ diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h index 95d52e1a26e..78471b05773 100644 --- a/src/include/utils/pgstat_internal.h +++ b/src/include/utils/pgstat_internal.h @@ -601,12 +601,6 @@ typedef struct PgStatShared_ReplSlot PgStat_StatReplSlotEntry stats; } PgStatShared_ReplSlot; -typedef struct PgStatShared_Backend -{ - PgStatShared_Common header; - PgStat_Backend stats; -} PgStatShared_Backend; - /* * Central shared memory entry for the cumulative stats system. * @@ -789,13 +783,6 @@ extern void pgstat_archiver_init_shmem_cb(void *stats); extern void pgstat_archiver_reset_all_cb(TimestampTz ts); extern void pgstat_archiver_snapshot_cb(void); -/* - * Functions in pgstat_backend.c - */ - -extern void pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, - TimestampTz ts); - /* * Functions in pgstat_bgwriter.c */ diff --git a/src/include/utils/pgstat_kind.h b/src/include/utils/pgstat_kind.h index 45ca599d0dd..489e8fa38bf 100644 --- a/src/include/utils/pgstat_kind.h +++ b/src/include/utils/pgstat_kind.h @@ -30,16 +30,15 @@ #define PGSTAT_KIND_FUNCTION 4 /* per-function statistics */ #define PGSTAT_KIND_REPLSLOT 5 /* per-slot statistics */ #define PGSTAT_KIND_SUBSCRIPTION 6 /* per-subscription statistics */ -#define PGSTAT_KIND_BACKEND 7 /* per-backend statistics */ /* stats for fixed-numbered objects */ -#define PGSTAT_KIND_ARCHIVER 8 -#define PGSTAT_KIND_BGWRITER 9 -#define PGSTAT_KIND_CHECKPOINTER 10 -#define PGSTAT_KIND_IO 11 -#define PGSTAT_KIND_LOCK 12 -#define PGSTAT_KIND_SLRU 13 -#define PGSTAT_KIND_WAL 14 +#define PGSTAT_KIND_ARCHIVER 7 +#define PGSTAT_KIND_BGWRITER 8 +#define PGSTAT_KIND_CHECKPOINTER 9 +#define PGSTAT_KIND_IO 10 +#define PGSTAT_KIND_LOCK 11 +#define PGSTAT_KIND_SLRU 12 +#define PGSTAT_KIND_WAL 13 #define PGSTAT_KIND_BUILTIN_MIN PGSTAT_KIND_DATABASE #define PGSTAT_KIND_BUILTIN_MAX PGSTAT_KIND_WAL diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 4255c1234f4..a53daf1338e 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -120,15 +120,14 @@ SELECT id, name, fixed_amount, 4 | function | f | f | t 5 | replslot | f | t | t 6 | subscription | f | t | t - 7 | backend | f | t | f - 8 | archiver | t | f | t - 9 | bgwriter | t | f | t - 10 | checkpointer | t | f | t - 11 | io | t | f | t - 12 | lock | t | f | t - 13 | slru | t | f | t - 14 | wal | t | f | t -(14 rows) + 7 | archiver | t | f | t + 8 | bgwriter | t | f | t + 9 | checkpointer | t | f | t + 10 | io | t | f | t + 11 | lock | t | f | t + 12 | slru | t | f | t + 13 | wal | t | f | t +(13 rows) -- ensure that both seqscan and indexscan plans are allowed SET enable_seqscan TO on; diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 48a1deb9bca..5db53416c7e 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -2316,7 +2316,6 @@ PgFdwSamplingMethod PgFdwScanState PgIfAddrCallback PgStatShared_Archiver -PgStatShared_Backend PgStatShared_BgWriter PgStatShared_Checkpointer PgStatShared_Common @@ -2338,7 +2337,6 @@ PgStatShared_Subscription PgStatShared_Wal PgStatShared_WalBackendEntry PgStat_ArchiverStats -PgStat_Backend PgStat_BackendIO PgStat_BackendSubEntry PgStat_BgWriterStats -- 2.34.1