From b2463dbbeaf838d17dd1301e8f55c51f7bca2b2d Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Thu, 13 Aug 2026 12:28:55 +0000 Subject: [PATCH v5 6/6] pgstat: remove PGSTAT_KIND_BACKEND After WAL, Lock, and IO have moved, PGSTAT_KIND_BACKEND contains no data. Remove that kind together with its shared structures, callbacks, and call sites. The generic per-backend statistics infrastructure can now take over pgstat_backend.c, whose previous contents implemented the removed kind. Rename pgstat_per_backend.c accordingly and adjust the build entries. Author: Bertrand Drouvot Reviewed-by: Michael Paquier Reviewed-by: Andres Freund 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 | 22 +- src/backend/utils/activity/pgstat_backend.c | 454 +++++++++++++----- .../utils/activity/pgstat_per_backend.c | 407 ---------------- 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 - 11 files changed, 358 insertions(+), 597 deletions(-) 92.7% src/backend/utils/activity/ 4.3% src/include/ diff --git a/src/backend/utils/activity/Makefile b/src/backend/utils/activity/Makefile index 8924b10ed2e..2e32d1485d6 100644 --- a/src/backend/utils/activity/Makefile +++ b/src/backend/utils/activity/Makefile @@ -29,7 +29,6 @@ OBJS = \ pgstat_io.o \ pgstat_kind.o \ pgstat_lock.o \ - pgstat_per_backend.o \ pgstat_relation.o \ pgstat_replslot.o \ pgstat_shmem.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..e6dcb2e26fc 100644 --- a/src/backend/utils/activity/meson.build +++ b/src/backend/utils/activity/meson.build @@ -14,7 +14,6 @@ backend_sources += files( 'pgstat_io.c', 'pgstat_kind.c', 'pgstat_lock.c', - 'pgstat_per_backend.c', 'pgstat_relation.c', 'pgstat_replslot.c', 'pgstat_shmem.c', diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c index 4ab306c06ce..398ec26a298 100644 --- a/src/backend/utils/activity/pgstat.c +++ b/src/backend/utils/activity/pgstat.c @@ -69,7 +69,7 @@ * To keep things manageable, stats handling is split across several * files. Infrastructure pieces are in: * - pgstat.c - this file, to tie it all together - * - pgstat_per_backend.c - generic per-backend statistics infrastructure + * - pgstat_backend.c - generic per-backend statistics infrastructure * - pgstat_shmem.c - nearly everything dealing with shared memory, including * the maintenance of hashtable entries * - pgstat_xact.c - transactional integration, including the transactional @@ -77,7 +77,6 @@ * * Each statistics kind is handled in a dedicated file: * - pgstat_archiver.c - * - pgstat_backend.c * - pgstat_bgwriter.c * - pgstat_checkpointer.c * - pgstat_database.c @@ -381,21 +380,6 @@ 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] = { @@ -684,10 +668,6 @@ 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_acc_my_per_backend_entries(); diff --git a/src/backend/utils/activity/pgstat_backend.c b/src/backend/utils/activity/pgstat_backend.c index b5996d15d8f..f3f08d578cf 100644 --- a/src/backend/utils/activity/pgstat_backend.c +++ b/src/backend/utils/activity/pgstat_backend.c @@ -1,17 +1,11 @@ /* ------------------------------------------------------------------------- * * pgstat_backend.c - * Implementation of backend statistics. + * Generic infrastructure for per-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. + * This file manages the per-kind arrays used for per-backend statistics, + * including entry creation, fetching, snapshots, transfer to global + * statistics, and invalidation. * * Copyright (c) 2001-2026, PostgreSQL Global Development Group * @@ -23,157 +17,393 @@ #include "postgres.h" #include "storage/proc.h" -#include "storage/procarray.h" #include "utils/pgstat_internal.h" /* - * Returns statistics of a backend by proc number. + * Return the shared-memory object for one built-in fixed-numbered statistics + * kind. */ -PgStat_Backend * -pgstat_fetch_stat_backend(ProcNumber procNumber) +static char * +pgstat_get_per_backend_shmem_data(PgStat_Kind kind) { - PgStat_Backend *backend_entry; + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - backend_entry = (PgStat_Backend *) pgstat_fetch_entry(PGSTAT_KIND_BACKEND, - InvalidOid, procNumber, - NULL); + Assert(kind_info != NULL); + Assert(kind_info->fixed_amount); + Assert(pgstat_is_kind_builtin(kind)); - return backend_entry; + return (char *) pgStatLocal.shmem + kind_info->shared_ctl_off; } /* - * Returns statistics of a backend by pid. + * Return one per-backend entry, whether or not it is currently active. * - * 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. + * Callers that inspect or modify the entry must hold its content lock. */ -PgStat_Backend * -pgstat_fetch_stat_backend_by_pid(int pid, BackendType *bktype) +void * +pgstat_get_per_backend_entry(PgStat_Kind kind, ProcNumber procnum) { - PGPROC *proc; - PgBackendStatus *beentry; - ProcNumber procNumber; - PgStat_Backend *backend_stats; + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + char *array; + Size aligned_entry_size; - proc = BackendPidGetProc(pid); - if (bktype) - *bktype = B_INVALID; + if (kind_info == NULL || kind_info->per_backend_entry_size == 0) + return NULL; - /* this could be an auxiliary process */ - if (!proc) - proc = AuxiliaryPidGetProc(pid); + Assert(pgstat_is_kind_builtin(kind)); - if (!proc) + if (procnum < 0 || procnum >= NumPerBackendStatSlots) return NULL; - procNumber = GetNumberFromPGProc(proc); + array = pgStatLocal.shmem->per_backend_arrays[kind]; + Assert(array != NULL); - beentry = pgstat_get_beentry_by_proc_number(procNumber); - if (!beentry) - return NULL; + /* + * The entry type is kind-specific, so use its aligned size as the byte + * stride for the zero-based ProcNumber. + */ + aligned_entry_size = MAXALIGN(kind_info->per_backend_entry_size); - /* check if the backend type tracks statistics */ - if (!pgstat_tracks_backend_bktype(beentry->st_backendType)) - return NULL; + return array + procnum * aligned_entry_size; +} - /* if PID does not match, leave */ - if (beentry->st_procpid != pid) - return NULL; +/* + * Initialize this process's entry for one per-backend statistics kind. + * + * A blocking flush during early startup may already have initialized the + * entry. In that case, preserve the statistics it contains. + */ +static PgStatShared_PerBackendEntry * +pgstat_create_my_per_backend_entry(PgStat_Kind kind) +{ + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + PgStatShared_PerBackendEntry *entry; - if (bktype) - *bktype = beentry->st_backendType; + entry = pgstat_get_per_backend_entry(kind, MyProcNumber); - /* - * 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) + LWLockAcquire(&entry->lock, LW_EXCLUSIVE); + + if (entry->backend_type == B_INVALID) { - if (bktype) - *bktype = B_INVALID; - return NULL; + entry->backend_type = MyBackendType; + memset((char *) entry + kind_info->per_backend_data_off, 0, + kind_info->per_backend_data_len); } - return backend_stats; + LWLockRelease(&entry->lock); + + return entry; } /* - * Create backend statistics entry for proc number. + * Initialize entries for all kinds that use per-backend arrays. + * + * This runs after any stale entries for the reused ProcNumber have been + * transferred to global statistics. */ void -pgstat_create_backend(ProcNumber procnum) +pgstat_create_my_per_backend_entries(void) { - PgStat_EntryRef *entry_ref; - PgStatShared_Backend *shstatent; + for (PgStat_Kind kind = PGSTAT_KIND_BUILTIN_MIN; + kind <= PGSTAT_KIND_BUILTIN_MAX; kind++) + { + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - entry_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_BACKEND, InvalidOid, - procnum, false); - shstatent = (PgStatShared_Backend *) entry_ref->shared_stats; + if (kind_info == NULL || kind_info->per_backend_entry_size == 0) + continue; - /* - * 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); + (void) pgstat_create_my_per_backend_entry(kind); + } } /* - * Backend statistics are not collected for all BackendTypes. + * Lock this process's entry for a per-backend statistics kind. + * + * The blocking path initializes an inactive entry, which allows forced + * flushes during early process startup. The routine nonblocking path does not + * initialize entries. * - * 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. + * NB: On success, the entry is returned with its content lock held. A + * nonblocking call returns NULL if the entry cannot be locked or is inactive. + */ +void * +pgstat_lock_my_per_backend_entry(PgStat_Kind kind, bool nowait) +{ + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + PgStatShared_PerBackendEntry *entry; + + entry = pgstat_get_per_backend_entry(kind, MyProcNumber); + + if (nowait) + { + if (!LWLockConditionalAcquire(&entry->lock, LW_EXCLUSIVE)) + return NULL; + + if (entry->backend_type == B_INVALID) + { + LWLockRelease(&entry->lock); + return NULL; + } + } + else + { + LWLockAcquire(&entry->lock, LW_EXCLUSIVE); + + if (entry->backend_type == B_INVALID) + { + entry->backend_type = MyBackendType; + memset((char *) entry + kind_info->per_backend_data_off, 0, + kind_info->per_backend_data_len); + } + } + + return entry; +} + +/* + * Accumulate all active per-backend entries into a fixed-kind snapshot. * - * Function returns true if BackendType participates in the backend stats - * subsystem and false if it does not. + * SNAPSHOT mode also copies every active entry into the backend-local + * snapshot hash, fixing both the values and the set of visible processes. + * The caller must hold the kind lock to prevent entries from moving into the + * global statistics while the snapshot is assembled. + */ +void +pgstat_per_backend_snapshot(PgStat_Kind kind, void *snap) +{ + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + PgStat_HashKey key = {0}; + + key.kind = kind; + key.dboid = InvalidOid; + + for (ProcNumber procnum = 0; procnum < NumPerBackendStatSlots; procnum++) + { + PgStatShared_PerBackendEntry *entry; + + entry = pgstat_get_per_backend_entry(kind, procnum); + + LWLockAcquire(&entry->lock, LW_SHARED); + + if (entry->backend_type != B_INVALID) + { + kind_info->per_backend_acc_cb(snap, entry); + + if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT) + { + key.objid = procnum; + pgstat_cache_snapshot_entry(&key, + (char *) entry + + kind_info->per_backend_data_off, + kind_info->per_backend_data_len); + } + } + + LWLockRelease(&entry->lock); + } +} + +/* + * Fetch one process's per-backend statistics. * - * When adding a new BackendType, also consider adding relevant restrictions to - * pgstat_tracks_io_object() and pgstat_tracks_io_op(). + * NONE mode returns a copy allocated in the current memory context. CACHE and + * SNAPSHOT modes return data owned by the backend-local statistics snapshot. + * Return NULL if the ProcNumber is invalid or no process was active at the + * consistency mode's observation point. */ -bool -pgstat_tracks_backend_bktype(BackendType bktype) +void * +pgstat_fetch_per_backend(PgStat_Kind kind, ProcNumber procnum) { + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + PgStatShared_PerBackendEntry *entry; + PgStat_HashKey key = {0}; + void *stats_data; + bool found; + + pgstat_prep_snapshot(); + + entry = pgstat_get_per_backend_entry(kind, procnum); + + if (entry == NULL) + return NULL; + + /* Read directly without caching in NONE mode */ + if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_NONE) + { + LWLockAcquire(&entry->lock, LW_SHARED); + + if (entry->backend_type == B_INVALID) + { + LWLockRelease(&entry->lock); + return NULL; + } + + stats_data = palloc(kind_info->per_backend_data_len); + memcpy(stats_data, (char *) entry + kind_info->per_backend_data_off, + kind_info->per_backend_data_len); + LWLockRelease(&entry->lock); + + return stats_data; + } + + Assert(pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_CACHE || + pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT); + /* - * List every type so that new backend types trigger a warning about - * needing to adjust this switch. + * A full fixed-kind snapshot pre-caches all active entries. CACHE mode + * reads only the requested array entry on a cache miss. */ - switch (bktype) + if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT) + pgstat_snapshot_fixed(kind); + else + pgStatLocal.snapshot.mode = PGSTAT_FETCH_CONSISTENCY_CACHE; + + key.kind = kind; + key.dboid = InvalidOid; + key.objid = procnum; + + stats_data = pgstat_lookup_snapshot_entry(&key, &found); + + if (found) + return stats_data; + + /* + * A miss after building a full snapshot means that the process was not + * active at the snapshot point. + */ + if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT) + return NULL; + + LWLockAcquire(&entry->lock, LW_SHARED); + + if (entry->backend_type == B_INVALID) + stats_data = pgstat_cache_snapshot_entry(&key, NULL, 0); + else + stats_data = pgstat_cache_snapshot_entry(&key, + (char *) entry + + kind_info->per_backend_data_off, + kind_info->per_backend_data_len); + + LWLockRelease(&entry->lock); + + return stats_data; +} + +/* + * Transfer this process's entry into global statistics and invalidate it. + * + * The kind lock serializes this transfer with global snapshots and resets. + * The entry lock serializes it with routine flushes and per-backend reads. + */ +static void +pgstat_acc_my_per_backend(PgStat_Kind kind) +{ + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + PgStatShared_PerBackendEntry *entry; + char *shared_struct; + LWLock *lock; + void *dst; + + entry = pgstat_get_per_backend_entry(kind, MyProcNumber); + + if (entry == NULL) + return; + + shared_struct = pgstat_get_per_backend_shmem_data(kind); + lock = (LWLock *) (shared_struct + + kind_info->per_backend_shared_lock_off); + dst = shared_struct + kind_info->shared_data_off; + + LWLockAcquire(lock, LW_EXCLUSIVE); + LWLockAcquire(&entry->lock, LW_EXCLUSIVE); + + if (entry->backend_type != B_INVALID) + { + kind_info->per_backend_acc_cb(dst, entry); + entry->backend_type = B_INVALID; + } + + LWLockRelease(&entry->lock); + LWLockRelease(lock); +} + +/* + * Transfer this process's entries for all per-backend statistics kinds. + * + * This is used both at process exit and before reusing a ProcNumber. + */ +void +pgstat_acc_my_per_backend_entries(void) +{ + for (PgStat_Kind kind = PGSTAT_KIND_BUILTIN_MIN; + kind <= PGSTAT_KIND_BUILTIN_MAX; kind++) + { + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + + if (kind_info == NULL || kind_info->per_backend_entry_size == 0) + continue; + + pgstat_acc_my_per_backend(kind); + } +} + +/* + * Transfer every active entry into global statistics and invalidate it. + * + * This is called during clean server shutdown before the statistics file is + * written. + */ +static void +pgstat_acc_all_per_backend(PgStat_Kind kind) +{ + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + char *shared_struct; + LWLock *lock; + void *dst; + + shared_struct = pgstat_get_per_backend_shmem_data(kind); + lock = (LWLock *) (shared_struct + + kind_info->per_backend_shared_lock_off); + dst = shared_struct + kind_info->shared_data_off; + + LWLockAcquire(lock, LW_EXCLUSIVE); + + for (ProcNumber procnum = 0; procnum < NumPerBackendStatSlots; procnum++) { - 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; + PgStatShared_PerBackendEntry *entry; + + entry = pgstat_get_per_backend_entry(kind, procnum); + + LWLockAcquire(&entry->lock, LW_EXCLUSIVE); + + if (entry->backend_type != B_INVALID) + { + kind_info->per_backend_acc_cb(dst, entry); + entry->backend_type = B_INVALID; + } + + LWLockRelease(&entry->lock); } - return false; + LWLockRelease(lock); } +/* + * Transfer all entries for all per-backend statistics kinds. + * + * The caller uses this before writing the statistics file at clean shutdown. + */ void -pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts) +pgstat_acc_all_per_backend_entries(void) { - ((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts; + for (PgStat_Kind kind = PGSTAT_KIND_BUILTIN_MIN; + kind <= PGSTAT_KIND_BUILTIN_MAX; kind++) + { + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + + if (kind_info == NULL || kind_info->per_backend_entry_size == 0) + continue; + + pgstat_acc_all_per_backend(kind); + } } diff --git a/src/backend/utils/activity/pgstat_per_backend.c b/src/backend/utils/activity/pgstat_per_backend.c deleted file mode 100644 index e866d109fa7..00000000000 --- a/src/backend/utils/activity/pgstat_per_backend.c +++ /dev/null @@ -1,407 +0,0 @@ -/* ------------------------------------------------------------------------- - * - * pgstat_per_backend.c - * Generic infrastructure for per-backend statistics. - * - * This file manages the per-kind arrays used for per-backend statistics, - * including entry creation, fetching, snapshots, transfer to global - * statistics, and invalidation. - * - * Copyright (c) 2001-2026, PostgreSQL Global Development Group - * - * IDENTIFICATION - * src/backend/utils/activity/pgstat_per_backend.c - * ------------------------------------------------------------------------- - */ - -#include "postgres.h" - -#include "storage/proc.h" -#include "utils/pgstat_internal.h" - -/* - * Return the shared-memory object for one built-in fixed-numbered statistics - * kind. - */ -static char * -pgstat_get_per_backend_shmem_data(PgStat_Kind kind) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - - Assert(kind_info != NULL); - Assert(kind_info->fixed_amount); - Assert(pgstat_is_kind_builtin(kind)); - - return (char *) pgStatLocal.shmem + kind_info->shared_ctl_off; -} - -/* - * Return one per-backend entry, whether or not it is currently active. - * - * Callers that inspect or modify the entry must hold its content lock. - */ -void * -pgstat_get_per_backend_entry(PgStat_Kind kind, ProcNumber procnum) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - char *array; - Size aligned_entry_size; - - if (kind_info == NULL || kind_info->per_backend_entry_size == 0) - return NULL; - - Assert(pgstat_is_kind_builtin(kind)); - - if (procnum < 0 || procnum >= NumPerBackendStatSlots) - return NULL; - - array = pgStatLocal.shmem->per_backend_arrays[kind]; - Assert(array != NULL); - - /* - * The entry type is kind-specific, so use its aligned size as the byte - * stride for the zero-based ProcNumber. - */ - aligned_entry_size = MAXALIGN(kind_info->per_backend_entry_size); - - return array + procnum * aligned_entry_size; -} - -/* - * Initialize this process's entry for one per-backend statistics kind. - * - * A blocking flush during early startup may already have initialized the - * entry. In that case, preserve the statistics it contains. - */ -static PgStatShared_PerBackendEntry * -pgstat_create_my_per_backend_entry(PgStat_Kind kind) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - PgStatShared_PerBackendEntry *entry; - - entry = pgstat_get_per_backend_entry(kind, MyProcNumber); - - LWLockAcquire(&entry->lock, LW_EXCLUSIVE); - - if (entry->backend_type == B_INVALID) - { - entry->backend_type = MyBackendType; - memset((char *) entry + kind_info->per_backend_data_off, 0, - kind_info->per_backend_data_len); - } - - LWLockRelease(&entry->lock); - - return entry; -} - -/* - * Initialize entries for all kinds that use per-backend arrays. - * - * This runs after any stale entries for the reused ProcNumber have been - * transferred to global statistics. - */ -void -pgstat_create_my_per_backend_entries(void) -{ - for (PgStat_Kind kind = PGSTAT_KIND_BUILTIN_MIN; - kind <= PGSTAT_KIND_BUILTIN_MAX; kind++) - { - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - - if (kind_info == NULL || kind_info->per_backend_entry_size == 0) - continue; - - (void) pgstat_create_my_per_backend_entry(kind); - } -} - -/* - * Lock this process's entry for a per-backend statistics kind. - * - * The blocking path initializes an inactive entry, which allows forced - * flushes during early process startup. The routine nonblocking path does not - * initialize entries. - * - * NB: On success, the entry is returned with its content lock held. A - * nonblocking call returns NULL if the entry cannot be locked or is inactive. - */ -void * -pgstat_lock_my_per_backend_entry(PgStat_Kind kind, bool nowait) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - PgStatShared_PerBackendEntry *entry; - - entry = pgstat_get_per_backend_entry(kind, MyProcNumber); - - if (nowait) - { - if (!LWLockConditionalAcquire(&entry->lock, LW_EXCLUSIVE)) - return NULL; - - if (entry->backend_type == B_INVALID) - { - LWLockRelease(&entry->lock); - return NULL; - } - } - else - { - LWLockAcquire(&entry->lock, LW_EXCLUSIVE); - - if (entry->backend_type == B_INVALID) - { - entry->backend_type = MyBackendType; - memset((char *) entry + kind_info->per_backend_data_off, 0, - kind_info->per_backend_data_len); - } - } - - return entry; -} - -/* - * Accumulate all active per-backend entries into a fixed-kind snapshot. - * - * SNAPSHOT mode also copies every active entry into the backend-local - * snapshot hash, fixing both the values and the set of visible processes. - * The caller must hold the kind lock to prevent entries from moving into the - * global statistics while the snapshot is assembled. - */ -void -pgstat_per_backend_snapshot(PgStat_Kind kind, void *snap) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - PgStat_HashKey key = {0}; - - key.kind = kind; - key.dboid = InvalidOid; - - for (ProcNumber procnum = 0; procnum < NumPerBackendStatSlots; procnum++) - { - PgStatShared_PerBackendEntry *entry; - - entry = pgstat_get_per_backend_entry(kind, procnum); - - LWLockAcquire(&entry->lock, LW_SHARED); - - if (entry->backend_type != B_INVALID) - { - kind_info->per_backend_acc_cb(snap, entry); - - if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT) - { - key.objid = procnum; - pgstat_cache_snapshot_entry(&key, - (char *) entry + - kind_info->per_backend_data_off, - kind_info->per_backend_data_len); - } - } - - LWLockRelease(&entry->lock); - } -} - -/* - * Fetch one process's per-backend statistics. - * - * NONE mode returns a copy allocated in the current memory context. CACHE and - * SNAPSHOT modes return data owned by the backend-local statistics snapshot. - * Return NULL if the ProcNumber is invalid or no process was active at the - * consistency mode's observation point. - */ -void * -pgstat_fetch_per_backend(PgStat_Kind kind, ProcNumber procnum) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - PgStatShared_PerBackendEntry *entry; - PgStat_HashKey key = {0}; - void *stats_data; - bool found; - - pgstat_prep_snapshot(); - - entry = pgstat_get_per_backend_entry(kind, procnum); - - if (entry == NULL) - return NULL; - - /* Read directly without caching in NONE mode */ - if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_NONE) - { - LWLockAcquire(&entry->lock, LW_SHARED); - - if (entry->backend_type == B_INVALID) - { - LWLockRelease(&entry->lock); - return NULL; - } - - stats_data = palloc(kind_info->per_backend_data_len); - memcpy(stats_data, (char *) entry + kind_info->per_backend_data_off, - kind_info->per_backend_data_len); - LWLockRelease(&entry->lock); - - return stats_data; - } - - Assert(pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_CACHE || - pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT); - - /* - * A full fixed-kind snapshot pre-caches all active entries. CACHE mode - * reads only the requested array entry on a cache miss. - */ - if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT) - pgstat_snapshot_fixed(kind); - else - pgStatLocal.snapshot.mode = PGSTAT_FETCH_CONSISTENCY_CACHE; - - key.kind = kind; - key.dboid = InvalidOid; - key.objid = procnum; - - stats_data = pgstat_lookup_snapshot_entry(&key, &found); - - if (found) - return stats_data; - - /* - * A miss after building a full snapshot means that the process was not - * active at the snapshot point. - */ - if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT) - return NULL; - - LWLockAcquire(&entry->lock, LW_SHARED); - - if (entry->backend_type == B_INVALID) - stats_data = pgstat_cache_snapshot_entry(&key, NULL, 0); - else - stats_data = pgstat_cache_snapshot_entry(&key, - (char *) entry + - kind_info->per_backend_data_off, - kind_info->per_backend_data_len); - - LWLockRelease(&entry->lock); - - return stats_data; -} - -/* - * Transfer this process's entry into global statistics and invalidate it. - * - * The kind lock serializes this transfer with global snapshots and resets. - * The entry lock serializes it with routine flushes and per-backend reads. - */ -static void -pgstat_acc_my_per_backend(PgStat_Kind kind) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - PgStatShared_PerBackendEntry *entry; - char *shared_struct; - LWLock *lock; - void *dst; - - entry = pgstat_get_per_backend_entry(kind, MyProcNumber); - - if (entry == NULL) - return; - - shared_struct = pgstat_get_per_backend_shmem_data(kind); - lock = (LWLock *) (shared_struct + kind_info->per_backend_shared_lock_off); - dst = shared_struct + kind_info->shared_data_off; - - LWLockAcquire(lock, LW_EXCLUSIVE); - LWLockAcquire(&entry->lock, LW_EXCLUSIVE); - - if (entry->backend_type != B_INVALID) - { - kind_info->per_backend_acc_cb(dst, entry); - entry->backend_type = B_INVALID; - } - - LWLockRelease(&entry->lock); - LWLockRelease(lock); -} - -/* - * Transfer this process's entries for all per-backend statistics kinds. - * - * This is used both at process exit and before reusing a ProcNumber. - */ -void -pgstat_acc_my_per_backend_entries(void) -{ - for (PgStat_Kind kind = PGSTAT_KIND_BUILTIN_MIN; - kind <= PGSTAT_KIND_BUILTIN_MAX; kind++) - { - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - - if (kind_info == NULL || kind_info->per_backend_entry_size == 0) - continue; - - pgstat_acc_my_per_backend(kind); - } -} - -/* - * Transfer every active entry into global statistics and invalidate it. - * - * This is called during clean server shutdown before the statistics file is - * written. - */ -static void -pgstat_acc_all_per_backend(PgStat_Kind kind) -{ - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - char *shared_struct; - LWLock *lock; - void *dst; - - shared_struct = pgstat_get_per_backend_shmem_data(kind); - lock = (LWLock *) (shared_struct + kind_info->per_backend_shared_lock_off); - dst = shared_struct + kind_info->shared_data_off; - - LWLockAcquire(lock, LW_EXCLUSIVE); - - for (ProcNumber procnum = 0; procnum < NumPerBackendStatSlots; procnum++) - { - PgStatShared_PerBackendEntry *entry; - - entry = pgstat_get_per_backend_entry(kind, procnum); - - LWLockAcquire(&entry->lock, LW_EXCLUSIVE); - - if (entry->backend_type != B_INVALID) - { - kind_info->per_backend_acc_cb(dst, entry); - entry->backend_type = B_INVALID; - } - - LWLockRelease(&entry->lock); - } - - LWLockRelease(lock); -} - -/* - * Transfer all entries for all per-backend statistics kinds. - * - * The caller uses this before writing the statistics file at clean shutdown. - */ -void -pgstat_acc_all_per_backend_entries(void) -{ - for (PgStat_Kind kind = PGSTAT_KIND_BUILTIN_MIN; - kind <= PGSTAT_KIND_BUILTIN_MAX; kind++) - { - const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - - if (kind_info == NULL || kind_info->per_backend_entry_size == 0) - continue; - - pgstat_acc_all_per_backend(kind); - } -} diff --git a/src/include/pgstat.h b/src/include/pgstat.h index d6e13ad9838..eb63cdaf5eb 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -594,15 +594,6 @@ 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 */ @@ -639,16 +630,6 @@ 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 9c88f411734..aa1858497ed 100644 --- a/src/include/utils/pgstat_internal.h +++ b/src/include/utils/pgstat_internal.h @@ -628,12 +628,6 @@ 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. * @@ -837,13 +831,6 @@ 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 9f1f635234d..4d9e6dd57d3 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 72b9e76d6d7..83bdece2add 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -2290,7 +2290,6 @@ PgFdwSamplingMethod PgFdwScanState PgIfAddrCallback PgStatShared_Archiver -PgStatShared_Backend PgStatShared_BgWriter PgStatShared_Checkpointer PgStatShared_Common @@ -2312,7 +2311,6 @@ PgStatShared_Subscription PgStatShared_Wal PgStatShared_WalBackendEntry PgStat_ArchiverStats -PgStat_Backend PgStat_BackendIO PgStat_BackendSubEntry PgStat_BgWriterStats -- 2.34.1