On Sun, Jul 28, 2024 at 10:03:56PM +0200, Dmitry Dolgov wrote: > So far I've got nothing against :)
I've looked again at the first patch of this series, and applied the first one. Another last-minute edit I have done is to use more consistently PgStat_Kind in the loops for the stats kinds across all the pgstats code. Attached is a rebased set of the rest, with 0001 now introducing the pluggable core part. -- Michael
From af5a2456f90bf02b993c7c718e45a4cd6d863c79 Mon Sep 17 00:00:00 2001 From: Michael Paquier <mich...@paquier.xyz> Date: Fri, 2 Aug 2024 05:42:52 +0900 Subject: [PATCH v3 1/5] Introduce pluggable APIs for Cumulative Statistics This commit adds support in the backend for $subject, allowing out-of-core extensions to add their own custom statistics kinds. The stats kinds are divided into two parts for efficiency: - The built-in stats kinds, with designated initializers. - The custom kinds, able to use a range of IDs (128 slots available as of this patch), with information saved in TopMemoryContext. Custom cumulative statistics can only be loaded with shared_preload_libraries at startup, and must allocate a unique ID shared across all the PostgreSQL extension ecosystem with the following wiki page: https://wiki.postgresql.org/wiki/CustomCumulativeStats This is able to support fixed-numbered (like WAL, archiver, bgwriter) and variable-numbered stats kinds. --- src/include/pgstat.h | 35 +++- src/include/utils/pgstat_internal.h | 22 ++- src/backend/utils/activity/pgstat.c | 231 +++++++++++++++++++--- src/backend/utils/activity/pgstat_shmem.c | 31 ++- src/backend/utils/adt/pgstatfuncs.c | 2 +- 5 files changed, 287 insertions(+), 34 deletions(-) diff --git a/src/include/pgstat.h b/src/include/pgstat.h index f84e9fdeca..cd93a0109b 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -35,6 +35,10 @@ /* The types of statistics entries */ #define PgStat_Kind uint32 +/* Range of IDs allowed, for built-in and custom kinds */ +#define PGSTAT_KIND_MIN 1 /* Minimum ID allowed */ +#define PGSTAT_KIND_MAX 256 /* Maximum ID allowed */ + /* use 0 for INVALID, to catch zero-initialized data */ #define PGSTAT_KIND_INVALID 0 @@ -53,9 +57,34 @@ #define PGSTAT_KIND_SLRU 10 #define PGSTAT_KIND_WAL 11 -#define PGSTAT_KIND_FIRST_VALID PGSTAT_KIND_DATABASE -#define PGSTAT_KIND_LAST PGSTAT_KIND_WAL -#define PGSTAT_NUM_KINDS (PGSTAT_KIND_LAST + 1) +#define PGSTAT_KIND_MIN_BUILTIN PGSTAT_KIND_DATABASE +#define PGSTAT_KIND_MAX_BUILTIN PGSTAT_KIND_WAL + +/* Custom stats kinds */ + +/* Range of IDs allowed for custom stats kinds */ +#define PGSTAT_KIND_CUSTOM_MIN 128 +#define PGSTAT_KIND_CUSTOM_MAX PGSTAT_KIND_MAX +#define PGSTAT_KIND_CUSTOM_SIZE (PGSTAT_KIND_CUSTOM_MAX - PGSTAT_KIND_CUSTOM_MIN + 1) + +/* + * PgStat_Kind to use for extensions that require an ID, but are still in + * development and have not reserved their own unique kind ID yet. See: + * https://wiki.postgresql.org/wiki/CustomCumulativeStats + */ +#define PGSTAT_KIND_EXPERIMENTAL 128 + +static inline bool +pgstat_is_kind_builtin(PgStat_Kind kind) +{ + return kind > PGSTAT_KIND_INVALID && kind <= PGSTAT_KIND_MAX_BUILTIN; +} + +static inline bool +pgstat_is_kind_custom(PgStat_Kind kind) +{ + return kind >= PGSTAT_KIND_CUSTOM_MIN && kind <= PGSTAT_KIND_CUSTOM_MAX; +} /* Values for track_functions GUC variable --- order is significant! */ typedef enum TrackFunctionsLevel diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h index 778f625ca1..39f63362a3 100644 --- a/src/include/utils/pgstat_internal.h +++ b/src/include/utils/pgstat_internal.h @@ -195,7 +195,8 @@ typedef struct PgStat_KindInfo /* * The size of an entry in the shared stats hash table (pointed to by - * PgStatShared_HashEntry->body). + * PgStatShared_HashEntry->body). For fixed-numbered statistics, this is + * the size of an entry in PgStat_ShmemControl->custom_data. */ uint32 shared_size; @@ -446,6 +447,13 @@ typedef struct PgStat_ShmemControl PgStatShared_IO io; PgStatShared_SLRU slru; PgStatShared_Wal wal; + + /* + * Custom stats data with fixed-numbered objects, indexed by (PgStat_Kind + * - PGSTAT_KIND_CUSTOM_MIN). + */ + void *custom_data[PGSTAT_KIND_CUSTOM_SIZE]; + } PgStat_ShmemControl; @@ -459,7 +467,7 @@ typedef struct PgStat_Snapshot /* time at which snapshot was taken */ TimestampTz snapshot_timestamp; - bool fixed_valid[PGSTAT_NUM_KINDS]; + bool fixed_valid[PGSTAT_KIND_MAX_BUILTIN + 1]; PgStat_ArchiverStats archiver; @@ -473,6 +481,14 @@ typedef struct PgStat_Snapshot PgStat_WalStats wal; + /* + * Data in snapshot for custom fixed-numbered statistics, indexed by + * (PgStat_Kind - PGSTAT_KIND_CUSTOM_MIN). Each entry is allocated in + * TopMemoryContext, for a size of shared_data_len. + */ + bool custom_valid[PGSTAT_KIND_CUSTOM_SIZE]; + void *custom_data[PGSTAT_KIND_CUSTOM_SIZE]; + /* to free snapshot in bulk */ MemoryContext context; struct pgstat_snapshot_hash *stats; @@ -516,6 +532,8 @@ static inline void *pgstat_get_entry_data(PgStat_Kind kind, PgStatShared_Common */ extern const PgStat_KindInfo *pgstat_get_kind_info(PgStat_Kind kind); +extern void pgstat_register_kind(PgStat_Kind kind, + const PgStat_KindInfo *kind_info); #ifdef USE_ASSERT_CHECKING extern void pgstat_assert_is_up(void); diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c index 143478aca0..9bc8baca9c 100644 --- a/src/backend/utils/activity/pgstat.c +++ b/src/backend/utils/activity/pgstat.c @@ -49,8 +49,16 @@ * pgStatPending list. Pending statistics updates are flushed out by * pgstat_report_stat(). * + * It is possible for external modules to define custom statistics kinds, + * that can use the same properties as any built-in stats kinds. Each custom + * stats kind needs to assign a unique ID to ensure that it does not overlap + * with other extensions. In order to reserve a unique stats kind ID, refer + * to https://wiki.postgresql.org/wiki/CustomCumulativeStats. + * * The behavior of different kinds of statistics is determined by the kind's - * entry in pgstat_kind_infos, see PgStat_KindInfo for details. + * entry in pgstat_kind_builtin_infos for all the built-in statistics kinds + * defined, and pgstat_kind_custom_infos for custom kinds registered at + * startup by pgstat_register_kind(). See PgStat_KindInfo for details. * * The consistency of read accesses to statistics can be configured using the * stats_fetch_consistency GUC (see config.sgml and monitoring.sgml for the @@ -175,6 +183,8 @@ typedef struct PgStat_SnapshotEntry static void pgstat_write_statsfile(XLogRecPtr redo); static void pgstat_read_statsfile(XLogRecPtr redo); +static void pgstat_init_snapshot_fixed(void); + static void pgstat_reset_after_failure(void); static bool pgstat_flush_pending_entries(bool nowait); @@ -252,7 +262,7 @@ static bool pgstat_is_shutdown = false; /* - * The different kinds of statistics. + * The different kinds of built-in statistics. * * If reasonably possible, handling specific to one kind of stats should go * through this abstraction, rather than making more of pgstat.c aware. @@ -264,7 +274,7 @@ static bool pgstat_is_shutdown = false; * seem to be a great way of doing that, given the split across multiple * files. */ -static const PgStat_KindInfo pgstat_kind_infos[PGSTAT_NUM_KINDS] = { +static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_MAX_BUILTIN + 1] = { /* stats kinds for variable-numbered objects */ @@ -437,6 +447,15 @@ static const PgStat_KindInfo pgstat_kind_infos[PGSTAT_NUM_KINDS] = { }, }; +/* + * Information about custom statistics kinds. + * + * These are saved in a different array than the built-in kinds to save + * in clarity with the initializations. + * + * Indexed by PGSTAT_KIND_CUSTOM_MIN, of size PGSTAT_KIND_CUSTOM_SIZE. + */ +static const PgStat_KindInfo **pgstat_kind_custom_infos = NULL; /* ------------------------------------------------------------ * Functions managing the state of the stats system for all backends. @@ -587,6 +606,8 @@ pgstat_initialize(void) pgstat_init_wal(); + pgstat_init_snapshot_fixed(); + /* Set up a process-exit hook to clean up */ before_shmem_exit(pgstat_shutdown_hook, 0); @@ -830,6 +851,8 @@ pgstat_clear_snapshot(void) memset(&pgStatLocal.snapshot.fixed_valid, 0, sizeof(pgStatLocal.snapshot.fixed_valid)); + memset(&pgStatLocal.snapshot.custom_valid, 0, + sizeof(pgStatLocal.snapshot.custom_valid)); pgStatLocal.snapshot.stats = NULL; pgStatLocal.snapshot.mode = PGSTAT_FETCH_CONSISTENCY_NONE; @@ -993,7 +1016,29 @@ pgstat_snapshot_fixed(PgStat_Kind kind) else pgstat_build_snapshot_fixed(kind); - Assert(pgStatLocal.snapshot.fixed_valid[kind]); + if (pgstat_is_kind_builtin(kind)) + Assert(pgStatLocal.snapshot.fixed_valid[kind]); + else if (pgstat_is_kind_custom(kind)) + Assert(pgStatLocal.snapshot.custom_valid[kind - PGSTAT_KIND_CUSTOM_MIN]); +} + +static void +pgstat_init_snapshot_fixed(void) +{ + /* + * Initialize fixed-numbered statistics data in snapshots, only for custom + * stats kinds. + */ + for (int kind = PGSTAT_KIND_CUSTOM_MIN; kind <= PGSTAT_KIND_CUSTOM_MAX; kind++) + { + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + + if (!kind_info || !kind_info->fixed_amount) + continue; + + pgStatLocal.snapshot.custom_data[kind - PGSTAT_KIND_CUSTOM_MIN] = + MemoryContextAlloc(TopMemoryContext, kind_info->shared_data_len); + } } static void @@ -1089,10 +1134,12 @@ pgstat_build_snapshot(void) /* * Build snapshot of all fixed-numbered stats. */ - for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++) + for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++) { const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + if (!kind_info) + continue; if (!kind_info->fixed_amount) { Assert(kind_info->snapshot_cb == NULL); @@ -1109,6 +1156,20 @@ static void pgstat_build_snapshot_fixed(PgStat_Kind kind) { const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + int idx; + bool *valid; + + /* Position in fixed_valid or custom_valid */ + if (pgstat_is_kind_builtin(kind)) + { + idx = kind; + valid = pgStatLocal.snapshot.fixed_valid; + } + else + { + idx = kind - PGSTAT_KIND_CUSTOM_MIN; + valid = pgStatLocal.snapshot.custom_valid; + } Assert(kind_info->fixed_amount); Assert(kind_info->snapshot_cb != NULL); @@ -1116,21 +1177,21 @@ pgstat_build_snapshot_fixed(PgStat_Kind kind) if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_NONE) { /* rebuild every time */ - pgStatLocal.snapshot.fixed_valid[kind] = false; + valid[idx] = false; } - else if (pgStatLocal.snapshot.fixed_valid[kind]) + else if (valid[idx]) { /* in snapshot mode we shouldn't get called again */ Assert(pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_CACHE); return; } - Assert(!pgStatLocal.snapshot.fixed_valid[kind]); + Assert(!valid[idx]); kind_info->snapshot_cb(); - Assert(!pgStatLocal.snapshot.fixed_valid[kind]); - pgStatLocal.snapshot.fixed_valid[kind] = true; + Assert(!valid[idx]); + valid[idx] = true; } @@ -1286,30 +1347,127 @@ pgstat_flush_pending_entries(bool nowait) PgStat_Kind pgstat_get_kind_from_str(char *kind_str) { - for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++) + for (PgStat_Kind kind = PGSTAT_KIND_MIN_BUILTIN; kind <= PGSTAT_KIND_MAX_BUILTIN; kind++) { - if (pg_strcasecmp(kind_str, pgstat_kind_infos[kind].name) == 0) + if (pg_strcasecmp(kind_str, pgstat_kind_builtin_infos[kind].name) == 0) return kind; } + /* Check the custom set of cumulative stats */ + if (pgstat_kind_custom_infos) + { + for (int kind = 0; kind < PGSTAT_KIND_CUSTOM_SIZE; kind++) + { + if (pgstat_kind_custom_infos[kind] && + pg_strcasecmp(kind_str, pgstat_kind_custom_infos[kind]->name) == 0) + return kind + PGSTAT_KIND_CUSTOM_MIN; + } + } + ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("invalid statistics kind: \"%s\"", kind_str))); - return PGSTAT_KIND_DATABASE; /* avoid compiler warnings */ + return PGSTAT_KIND_INVALID; /* avoid compiler warnings */ } static inline bool pgstat_is_kind_valid(PgStat_Kind kind) { - return kind >= PGSTAT_KIND_FIRST_VALID && kind <= PGSTAT_KIND_LAST; + return pgstat_is_kind_builtin(kind) || pgstat_is_kind_custom(kind); } const PgStat_KindInfo * pgstat_get_kind_info(PgStat_Kind kind) { - Assert(pgstat_is_kind_valid(kind)); + if (pgstat_is_kind_builtin(kind)) + return &pgstat_kind_builtin_infos[kind]; - return &pgstat_kind_infos[kind]; + if (pgstat_is_kind_custom(kind)) + { + uint32 idx = kind - PGSTAT_KIND_CUSTOM_MIN; + + if (pgstat_kind_custom_infos == NULL || + pgstat_kind_custom_infos[idx] == NULL) + return NULL; + return pgstat_kind_custom_infos[idx]; + } + + return NULL; +} + +/* + * Register a new stats kind. + * + * PgStat_Kinds must be globally unique across all extensions. Refer + * to https://wiki.postgresql.org/wiki/CustomCumulativeStats to reserve a + * unique ID for your extension, to avoid conflicts with other extension + * developers. During development, use PGSTAT_KIND_EXPERIMENTAL to avoid + * needlessly reserving a new ID. + */ +void +pgstat_register_kind(PgStat_Kind kind, const PgStat_KindInfo *kind_info) +{ + uint32 idx = kind - PGSTAT_KIND_CUSTOM_MIN; + + if (kind_info->name == NULL || strlen(kind_info->name) == 0) + ereport(ERROR, + (errmsg("custom cumulative statistics name is invalid"), + errhint("Provide a non-empty name for the custom cumulative statistics."))); + + if (!pgstat_is_kind_custom(kind)) + ereport(ERROR, (errmsg("custom cumulative statistics ID %u is out of range", kind), + errhint("Provide a custom cumulative statistics ID between %u and %u.", + PGSTAT_KIND_CUSTOM_MIN, PGSTAT_KIND_CUSTOM_MAX))); + + if (!process_shared_preload_libraries_in_progress) + ereport(ERROR, + (errmsg("failed to register custom cumulative statistics \"%s\" with ID %u", kind_info->name, kind), + errdetail("Custom cumulative statistics must be registered while initializing modules in \"shared_preload_libraries\"."))); + + /* + * Check some data for fixed-numbered stats. + */ + if (kind_info->fixed_amount) + { + if (kind_info->shared_size == 0) + ereport(ERROR, + (errmsg("custom cumulative statistics property is invalid"), + errhint("Custom cumulative statistics require a shared memory size for fixed-numbered objects."))); + } + + /* + * If pgstat_kind_custom_infos is not available yet, allocate it. + */ + if (pgstat_kind_custom_infos == NULL) + { + pgstat_kind_custom_infos = (const PgStat_KindInfo **) + MemoryContextAllocZero(TopMemoryContext, + sizeof(PgStat_KindInfo *) * PGSTAT_KIND_CUSTOM_SIZE); + } + + if (pgstat_kind_custom_infos[idx] != NULL && + pgstat_kind_custom_infos[idx]->name != NULL) + ereport(ERROR, + (errmsg("failed to register custom cumulative statistics \"%s\" with ID %u", kind_info->name, kind), + errdetail("Custom cumulative statistics \"%s\" already registered with the same ID.", + pgstat_kind_custom_infos[idx]->name))); + + /* check for existing custom stats with the same name */ + for (int existing_kind = 0; existing_kind < PGSTAT_KIND_CUSTOM_SIZE; existing_kind++) + { + if (pgstat_kind_custom_infos[existing_kind] == NULL) + continue; + if (!pg_strcasecmp(pgstat_kind_custom_infos[existing_kind]->name, kind_info->name)) + ereport(ERROR, + (errmsg("failed to register custom cumulative statistics \"%s\" with ID %u", kind_info->name, kind), + errdetail("Existing cumulative statistics with ID %u has the same name.", existing_kind + PGSTAT_KIND_CUSTOM_MIN))); + } + + /* Register it */ + pgstat_kind_custom_infos[idx] = kind_info; + ereport(LOG, + (errmsg("registered custom cumulative statistics \"%s\" with ID %u", + kind_info->name, kind))); } /* @@ -1393,18 +1551,22 @@ pgstat_write_statsfile(XLogRecPtr redo) write_chunk_s(fpout, &redo); /* Write various stats structs for fixed number of objects */ - for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++) + for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++) { char *ptr; const PgStat_KindInfo *info = pgstat_get_kind_info(kind); - if (!info->fixed_amount) + if (!info || !info->fixed_amount) continue; - Assert(info->snapshot_ctl_off != 0); + if (pgstat_is_kind_builtin(kind)) + Assert(info->snapshot_ctl_off != 0); pgstat_build_snapshot_fixed(kind); - ptr = ((char *) &pgStatLocal.snapshot) + info->snapshot_ctl_off; + if (pgstat_is_kind_builtin(kind)) + ptr = ((char *) &pgStatLocal.snapshot) + info->snapshot_ctl_off; + else + ptr = pgStatLocal.snapshot.custom_data[kind - PGSTAT_KIND_CUSTOM_MIN]; fputc(PGSTAT_FILE_ENTRY_FIXED, fpout); write_chunk_s(fpout, &kind); @@ -1427,6 +1589,17 @@ pgstat_write_statsfile(XLogRecPtr redo) if (ps->dropped) continue; + /* + * This discards data related to custom stats kinds that are unknown + * to this process. + */ + if (!pgstat_is_kind_valid(ps->key.kind)) + { + elog(WARNING, "found unknown stats entry %u/%u/%u", + ps->key.kind, ps->key.dboid, ps->key.objoid); + continue; + } + shstats = (PgStatShared_Common *) dsa_get_address(pgStatLocal.dsa, ps->body); kind_info = pgstat_get_kind_info(ps->key.kind); @@ -1613,8 +1786,16 @@ pgstat_read_statsfile(XLogRecPtr redo) } /* Load back stats into shared memory */ - ptr = ((char *) shmem) + info->shared_ctl_off + - info->shared_data_off; + if (pgstat_is_kind_builtin(kind)) + ptr = ((char *) shmem) + info->shared_ctl_off + + info->shared_data_off; + else + { + int idx = kind - PGSTAT_KIND_CUSTOM_MIN; + + ptr = ((char *) shmem->custom_data[idx]) + + info->shared_data_off; + } if (!read_chunk(fpin, ptr, info->shared_data_len)) { @@ -1711,7 +1892,7 @@ pgstat_read_statsfile(XLogRecPtr redo) if (found) { dshash_release_lock(pgStatLocal.shared_hash, p); - elog(WARNING, "found duplicate stats entry %d/%u/%u of type %c", + elog(WARNING, "found duplicate stats entry %u/%u/%u of type %c", key.kind, key.dboid, key.objoid, t); goto error; } @@ -1777,11 +1958,11 @@ pgstat_reset_after_failure(void) TimestampTz ts = GetCurrentTimestamp(); /* reset fixed-numbered stats */ - for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++) + for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++) { const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); - if (!kind_info->fixed_amount) + if (!kind_info || !kind_info->fixed_amount) continue; kind_info->reset_all_cb(ts); diff --git a/src/backend/utils/activity/pgstat_shmem.c b/src/backend/utils/activity/pgstat_shmem.c index 2d5f7d46de..c0ac9e4bbc 100644 --- a/src/backend/utils/activity/pgstat_shmem.c +++ b/src/backend/utils/activity/pgstat_shmem.c @@ -131,6 +131,21 @@ StatsShmemSize(void) sz = MAXALIGN(sizeof(PgStat_ShmemControl)); sz = add_size(sz, pgstat_dsa_init_size()); + /* Add shared memory for all the custom fixed-numbered statistics */ + for (int kind = PGSTAT_KIND_CUSTOM_MIN; kind <= PGSTAT_KIND_CUSTOM_MAX; kind++) + { + const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); + + if (!kind_info) + continue; + if (!kind_info->fixed_amount) + continue; + + Assert(kind_info->shared_size != 0); + + sz += MAXALIGN(kind_info->shared_size); + } + return sz; } @@ -197,15 +212,25 @@ StatsShmemInit(void) pg_atomic_init_u64(&ctl->gc_request_count, 1); /* initialize fixed-numbered stats */ - for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++) + for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++) { const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind); char *ptr; - if (!kind_info->fixed_amount) + if (!kind_info || !kind_info->fixed_amount) continue; - ptr = ((char *) ctl) + kind_info->shared_ctl_off; + if (pgstat_is_kind_builtin(kind)) + ptr = ((char *) ctl) + kind_info->shared_ctl_off; + else + { + int idx = kind - PGSTAT_KIND_CUSTOM_MIN; + + Assert(kind_info->shared_size != 0); + ctl->custom_data[idx] = ShmemAlloc(kind_info->shared_size); + ptr = ctl->custom_data[idx]; + } + kind_info->init_shmem_cb(ptr); } } diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index 3876339ee1..3221137123 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -1696,7 +1696,7 @@ pg_stat_reset(PG_FUNCTION_ARGS) * Reset some shared cluster-wide counters * * When adding a new reset target, ideally the name should match that in - * pgstat_kind_infos, if relevant. + * pgstat_kind_builtin_infos, if relevant. */ Datum pg_stat_reset_shared(PG_FUNCTION_ARGS) -- 2.45.2
From 5bcbe74bdb930ce1bd46791419e5fdd195b5f0d4 Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@paquier.xyz>
Date: Thu, 18 Jul 2024 14:10:35 +0900
Subject: [PATCH v3 2/5] Add helper routines to retrieve custom data for
fixed-numbered stats
This is useful for extensions to get snapshot and shmem data for custom
statistics, so as these don't need to know about the current snapshots.
---
src/include/utils/pgstat_internal.h | 32 +++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 39f63362a3..6bbd49388c 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -525,6 +525,8 @@ static inline int pgstat_cmp_hash_key(const void *a, const void *b, size_t size,
static inline uint32 pgstat_hash_hash_key(const void *d, size_t size, void *arg);
static inline size_t pgstat_get_entry_len(PgStat_Kind kind);
static inline void *pgstat_get_entry_data(PgStat_Kind kind, PgStatShared_Common *entry);
+static inline void *pgstat_get_custom_shmem_data(PgStat_Kind kind);
+static inline void *pgstat_get_custom_snapshot_data(PgStat_Kind kind);
/*
@@ -842,4 +844,34 @@ pgstat_get_entry_data(PgStat_Kind kind, PgStatShared_Common *entry)
return ((char *) (entry)) + off;
}
+/*
+ * Returns a pointer to the shared memory area of custom stats for
+ * fixed-numbered statistics.
+ */
+static inline void *
+pgstat_get_custom_shmem_data(PgStat_Kind kind)
+{
+ int idx = kind - PGSTAT_KIND_CUSTOM_MIN;
+
+ Assert(pgstat_is_kind_custom(kind));
+ Assert(pgstat_get_kind_info(kind)->fixed_amount);
+
+ return pgStatLocal.shmem->custom_data[idx];
+}
+
+/*
+ * Returns a pointer to the portion of custom data for fixed-numbered
+ * statistics in the current snapshot.
+ */
+static inline void *
+pgstat_get_custom_snapshot_data(PgStat_Kind kind)
+{
+ int idx = kind - PGSTAT_KIND_CUSTOM_MIN;
+
+ Assert(pgstat_is_kind_custom(kind));
+ Assert(pgstat_get_kind_info(kind)->fixed_amount);
+
+ return pgStatLocal.snapshot.custom_data[idx];
+}
+
#endif /* PGSTAT_INTERNAL_H */
--
2.45.2
From 99d3799031bd7d8f6f19880c356337fe14208e9a Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@paquier.xyz>
Date: Thu, 18 Jul 2024 14:14:58 +0900
Subject: [PATCH v3 3/5] doc: Add section for Custom Cumulative Statistics APIs
This provides a short description of what can be done, with a pointer to
the template in the tree.
---
doc/src/sgml/xfunc.sgml | 62 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)
diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index bf76490cbc..fbdbdbd883 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -3864,6 +3864,68 @@ extern bool InjectionPointDetach(const char *name);
</para>
</sect2>
+ <sect2 id="xfunc-addin-custom-cumulative-statistics">
+ <title>Custom Cumulative Statistics</title>
+
+ <para>
+ Is is possible for add-ins written in C-language to use custom types
+ of cumulative statistics registered in the
+ <link linkend="monitoring-stats-setup">Cumulative Statistics System</link>.
+ </para>
+
+ <para>
+ First, define a <literal>PgStat_KindInfo</literal> that includes all
+ the information related to the custom type registered. For example:
+<programlisting>
+static const PgStat_KindInfo custom_stats = {
+ .name = "custom_stats",
+ .fixed_amount = false,
+ .shared_size = sizeof(PgStatShared_Custom),
+ .shared_data_off = offsetof(PgStatShared_Custom, stats),
+ .shared_data_len = sizeof(((PgStatShared_Custom *) 0)->stats),
+ .pending_size = sizeof(PgStat_StatCustomEntry),
+}
+</programlisting>
+
+ Then, each backend that needs to use this custom type needs to register
+ it with <literal>pgstat_register_kind</literal> and a unique ID used to
+ store the entries related to this type of statistics:
+<programlisting>
+extern PgStat_Kind pgstat_add_kind(PgStat_Kind kind,
+ const PgStat_KindInfo *kind_info);
+</programlisting>
+ While developing a new extension, use
+ <literal>PGSTAT_KIND_EXPERIMENTAL</literal> for
+ <parameter>kind</parameter>. When you are ready to release the extension
+ to users, reserve a kind ID at the
+ <ulink url="https://wiki.postgresql.org/wiki/CustomCumulativeStats";>
+ Custom Cumulative Statistics</ulink> page.
+ </para>
+
+ <para>
+ The details of the API for <literal>PgStat_KindInfo</literal> can
+ be found in <filename>src/include/utils/pgstat_internal.h</filename>.
+ </para>
+
+ <para>
+ The type of statistics registered is associated with a name and a unique
+ ID shared across the server in shared memory. Each backend using a
+ custom type of statistics maintains a local cache storing the information
+ of each custom <literal>PgStat_KindInfo</literal>.
+ </para>
+
+ <para>
+ Place the extension module implementing the custom cumulative statistics
+ type in <xref linkend="guc-shared-preload-libraries"/> so that it will
+ be loaded early during <productname>PostgreSQL</productname> startup.
+ </para>
+
+ <para>
+ An example describing how to register and use custom statistics can be
+ found in <filename>src/test/modules/injection_points</filename>.
+ </para>
+ </sect2>
+
<sect2 id="extend-cpp">
<title>Using C++ for Extensibility</title>
--
2.45.2
From 47dacf574ece0f3b348c02e2a78ef602c3f14a23 Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@paquier.xyz>
Date: Thu, 18 Jul 2024 14:22:54 +0900
Subject: [PATCH v3 4/5] injection_points: Add statistics for custom points
This acts as a template of what can be achieved with the pluggable
cumulative stats APIs, while being useful on its own for injection
points.
Currently, the only data gathered is the number of times an injection
point is called. This can be extended as required. All the routines
related to the stats are located in their own file, for clarity.
A TAP test is included to provide coverage for these new APIs, showing
the persistency of the data across restarts.
---
src/test/modules/injection_points/Makefile | 11 +-
.../injection_points--1.0.sql | 10 +
.../injection_points/injection_points.c | 27 +++
.../injection_points/injection_stats.c | 197 ++++++++++++++++++
.../injection_points/injection_stats.h | 23 ++
src/test/modules/injection_points/meson.build | 9 +
.../modules/injection_points/t/001_stats.pl | 48 +++++
src/tools/pgindent/typedefs.list | 2 +
8 files changed, 325 insertions(+), 2 deletions(-)
create mode 100644 src/test/modules/injection_points/injection_stats.c
create mode 100644 src/test/modules/injection_points/injection_stats.h
create mode 100644 src/test/modules/injection_points/t/001_stats.pl
diff --git a/src/test/modules/injection_points/Makefile b/src/test/modules/injection_points/Makefile
index 2ffd2f77ed..7b9cd12a2a 100644
--- a/src/test/modules/injection_points/Makefile
+++ b/src/test/modules/injection_points/Makefile
@@ -1,7 +1,10 @@
# src/test/modules/injection_points/Makefile
-MODULES = injection_points
-
+MODULE_big = injection_points
+OBJS = \
+ $(WIN32RES) \
+ injection_points.o \
+ injection_stats.o
EXTENSION = injection_points
DATA = injection_points--1.0.sql
PGFILEDESC = "injection_points - facility for injection points"
@@ -11,9 +14,13 @@ REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
ISOLATION = inplace
+TAP_TESTS = 1
+
# The injection points are cluster-wide, so disable installcheck
NO_INSTALLCHECK = 1
+export enable_injection_points enable_injection_points
+
ifdef USE_PGXS
PG_CONFIG = pg_config
PGXS := $(shell $(PG_CONFIG) --pgxs)
diff --git a/src/test/modules/injection_points/injection_points--1.0.sql b/src/test/modules/injection_points/injection_points--1.0.sql
index 0f280419a5..b98d571889 100644
--- a/src/test/modules/injection_points/injection_points--1.0.sql
+++ b/src/test/modules/injection_points/injection_points--1.0.sql
@@ -74,3 +74,13 @@ CREATE FUNCTION injection_points_detach(IN point_name TEXT)
RETURNS void
AS 'MODULE_PATHNAME', 'injection_points_detach'
LANGUAGE C STRICT PARALLEL UNSAFE;
+
+--
+-- injection_points_stats_numcalls()
+--
+-- Reports statistics, if any, related to the given injection point.
+--
+CREATE FUNCTION injection_points_stats_numcalls(IN point_name TEXT)
+RETURNS bigint
+AS 'MODULE_PATHNAME', 'injection_points_stats_numcalls'
+LANGUAGE C STRICT;
diff --git a/src/test/modules/injection_points/injection_points.c b/src/test/modules/injection_points/injection_points.c
index 15f9d0233c..acec4e95b0 100644
--- a/src/test/modules/injection_points/injection_points.c
+++ b/src/test/modules/injection_points/injection_points.c
@@ -18,6 +18,7 @@
#include "postgres.h"
#include "fmgr.h"
+#include "injection_stats.h"
#include "miscadmin.h"
#include "nodes/pg_list.h"
#include "nodes/value.h"
@@ -170,6 +171,9 @@ injection_points_cleanup(int code, Datum arg)
char *name = strVal(lfirst(lc));
(void) InjectionPointDetach(name);
+
+ /* Remove stats entry */
+ pgstat_drop_inj(name);
}
}
@@ -182,6 +186,8 @@ injection_error(const char *name, const void *private_data)
if (!injection_point_allowed(condition))
return;
+ pgstat_report_inj(name);
+
elog(ERROR, "error triggered for injection point %s", name);
}
@@ -193,6 +199,8 @@ injection_notice(const char *name, const void *private_data)
if (!injection_point_allowed(condition))
return;
+ pgstat_report_inj(name);
+
elog(NOTICE, "notice triggered for injection point %s", name);
}
@@ -211,6 +219,8 @@ injection_wait(const char *name, const void *private_data)
if (!injection_point_allowed(condition))
return;
+ pgstat_report_inj(name);
+
/*
* Use the injection point name for this custom wait event. Note that
* this custom wait event name is not released, but we don't care much for
@@ -299,6 +309,10 @@ injection_points_attach(PG_FUNCTION_ARGS)
inj_list_local = lappend(inj_list_local, makeString(pstrdup(name)));
MemoryContextSwitchTo(oldctx);
}
+
+ /* Add entry for stats */
+ pgstat_create_inj(name);
+
PG_RETURN_VOID();
}
@@ -431,5 +445,18 @@ injection_points_detach(PG_FUNCTION_ARGS)
MemoryContextSwitchTo(oldctx);
}
+ /* Remove stats entry */
+ pgstat_drop_inj(name);
+
PG_RETURN_VOID();
}
+
+
+void
+_PG_init(void)
+{
+ if (!process_shared_preload_libraries_in_progress)
+ return;
+
+ pgstat_register_inj();
+}
diff --git a/src/test/modules/injection_points/injection_stats.c b/src/test/modules/injection_points/injection_stats.c
new file mode 100644
index 0000000000..78042074ff
--- /dev/null
+++ b/src/test/modules/injection_points/injection_stats.c
@@ -0,0 +1,197 @@
+/*--------------------------------------------------------------------------
+ *
+ * injection_stats.c
+ * Code for statistics of injection points.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/test/modules/injection_points/injection_stats.c
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "fmgr.h"
+
+#include "common/hashfn.h"
+#include "injection_stats.h"
+#include "pgstat.h"
+#include "utils/builtins.h"
+#include "utils/pgstat_internal.h"
+
+/* Structures for statistics of injection points */
+typedef struct PgStat_StatInjEntry
+{
+ PgStat_Counter numcalls; /* number of times point has been run */
+} PgStat_StatInjEntry;
+
+typedef struct PgStatShared_InjectionPoint
+{
+ PgStatShared_Common header;
+ PgStat_StatInjEntry stats;
+} PgStatShared_InjectionPoint;
+
+static bool injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait);
+
+static const PgStat_KindInfo injection_stats = {
+ .name = "injection_points",
+ .fixed_amount = false, /* Bounded by the number of points */
+
+ /* Injection points are system-wide */
+ .accessed_across_databases = true,
+
+ .shared_size = sizeof(PgStatShared_InjectionPoint),
+ .shared_data_off = offsetof(PgStatShared_InjectionPoint, stats),
+ .shared_data_len = sizeof(((PgStatShared_InjectionPoint *) 0)->stats),
+ .pending_size = sizeof(PgStat_StatInjEntry),
+ .flush_pending_cb = injection_stats_flush_cb,
+};
+
+/*
+ * Compute stats entry idx from point name with a 4-byte hash.
+ */
+#define PGSTAT_INJ_IDX(name) hash_bytes((const unsigned char *) name, strlen(name))
+
+/*
+ * Kind ID reserved for statistics of injection points.
+ */
+#define PGSTAT_KIND_INJECTION 129
+
+/* Track if stats are loaded */
+static bool inj_stats_loaded = false;
+
+/*
+ * Callback for stats handling
+ */
+static bool
+injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait)
+{
+ PgStat_StatInjEntry *localent;
+ PgStatShared_InjectionPoint *shfuncent;
+
+ localent = (PgStat_StatInjEntry *) entry_ref->pending;
+ shfuncent = (PgStatShared_InjectionPoint *) entry_ref->shared_stats;
+
+ if (!pgstat_lock_entry(entry_ref, nowait))
+ return false;
+
+ shfuncent->stats.numcalls += localent->numcalls;
+ return true;
+}
+
+/*
+ * Support function for the SQL-callable pgstat* functions. Returns
+ * a pointer to the injection point statistics struct.
+ */
+static PgStat_StatInjEntry *
+pgstat_fetch_stat_injentry(const char *name)
+{
+ PgStat_StatInjEntry *entry = NULL;
+
+ if (!inj_stats_loaded)
+ return NULL;
+
+ /* Compile the lookup key as a hash of the point name */
+ entry = (PgStat_StatInjEntry *) pgstat_fetch_entry(PGSTAT_KIND_INJECTION,
+ InvalidOid,
+ PGSTAT_INJ_IDX(name));
+ return entry;
+}
+
+/*
+ * Workhorse to do the registration work, called in _PG_init().
+ */
+void
+pgstat_register_inj(void)
+{
+ pgstat_register_kind(PGSTAT_KIND_INJECTION, &injection_stats);
+
+ /* mark stats as loaded */
+ inj_stats_loaded = true;
+}
+
+/*
+ * Report injection point creation.
+ */
+void
+pgstat_create_inj(const char *name)
+{
+ PgStat_EntryRef *entry_ref;
+ PgStatShared_InjectionPoint *shstatent;
+
+ /* leave if disabled */
+ if (!inj_stats_loaded)
+ return;
+
+ entry_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_INJECTION, InvalidOid,
+ PGSTAT_INJ_IDX(name), false);
+ shstatent = (PgStatShared_InjectionPoint *) entry_ref->shared_stats;
+
+ /* initialize shared memory data */
+ memset(&shstatent->stats, 0, sizeof(shstatent->stats));
+ pgstat_unlock_entry(entry_ref);
+}
+
+/*
+ * Report injection point drop.
+ */
+void
+pgstat_drop_inj(const char *name)
+{
+ /* leave if disabled */
+ if (!inj_stats_loaded)
+ return;
+
+ if (!pgstat_drop_entry(PGSTAT_KIND_INJECTION, InvalidOid,
+ PGSTAT_INJ_IDX(name)))
+ pgstat_request_entry_refs_gc();
+}
+
+/*
+ * Report statistics for injection point.
+ *
+ * This is simple because the set of stats to report currently is simple:
+ * track the number of times a point has been run.
+ */
+void
+pgstat_report_inj(const char *name)
+{
+ PgStat_EntryRef *entry_ref;
+ PgStatShared_InjectionPoint *shstatent;
+ PgStat_StatInjEntry *statent;
+
+ /* leave if disabled */
+ if (!inj_stats_loaded)
+ return;
+
+ entry_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_INJECTION, InvalidOid,
+ PGSTAT_INJ_IDX(name), false);
+
+ shstatent = (PgStatShared_InjectionPoint *) entry_ref->shared_stats;
+ statent = &shstatent->stats;
+
+ /* Update the injection point statistics */
+ statent->numcalls++;
+
+ pgstat_unlock_entry(entry_ref);
+}
+
+/*
+ * SQL function returning the number of times an injection point
+ * has been called.
+ */
+PG_FUNCTION_INFO_V1(injection_points_stats_numcalls);
+Datum
+injection_points_stats_numcalls(PG_FUNCTION_ARGS)
+{
+ char *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+ PgStat_StatInjEntry *entry = pgstat_fetch_stat_injentry(name);
+
+ if (entry == NULL)
+ PG_RETURN_NULL();
+
+ PG_RETURN_INT64(entry->numcalls);
+}
diff --git a/src/test/modules/injection_points/injection_stats.h b/src/test/modules/injection_points/injection_stats.h
new file mode 100644
index 0000000000..3e99705483
--- /dev/null
+++ b/src/test/modules/injection_points/injection_stats.h
@@ -0,0 +1,23 @@
+/*--------------------------------------------------------------------------
+ *
+ * injection_stats.h
+ * Definitions for statistics of injection points.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/test/modules/injection_points/injection_stats.h
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#ifndef INJECTION_STATS
+#define INJECTION_STATS
+
+extern void pgstat_register_inj(void);
+extern void pgstat_create_inj(const char *name);
+extern void pgstat_drop_inj(const char *name);
+extern void pgstat_report_inj(const char *name);
+
+#endif
diff --git a/src/test/modules/injection_points/meson.build b/src/test/modules/injection_points/meson.build
index 3c23c14d81..a52fe5121e 100644
--- a/src/test/modules/injection_points/meson.build
+++ b/src/test/modules/injection_points/meson.build
@@ -6,6 +6,7 @@ endif
injection_points_sources = files(
'injection_points.c',
+ 'injection_stats.c',
)
if host_system == 'windows'
@@ -42,4 +43,12 @@ tests += {
'inplace',
],
},
+ 'tap': {
+ 'env': {
+ 'enable_injection_points': get_option('injection_points') ? 'yes' : 'no',
+ },
+ 'tests': [
+ 't/001_stats.pl',
+ ],
+ },
}
diff --git a/src/test/modules/injection_points/t/001_stats.pl b/src/test/modules/injection_points/t/001_stats.pl
new file mode 100644
index 0000000000..7d5a96e522
--- /dev/null
+++ b/src/test/modules/injection_points/t/001_stats.pl
@@ -0,0 +1,48 @@
+
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+use strict;
+use warnings FATAL => 'all';
+use locale;
+
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Test persistency of statistics generated for injection points.
+if ($ENV{enable_injection_points} ne 'yes')
+{
+ plan skip_all => 'Injection points not supported by this build';
+}
+
+# Node initialization
+my $node = PostgreSQL::Test::Cluster->new('master');
+$node->init;
+$node->append_conf('postgresql.conf',
+ "shared_preload_libraries = 'injection_points'");
+$node->start;
+$node->safe_psql('postgres', 'CREATE EXTENSION injection_points;');
+
+# This should count for two calls.
+$node->safe_psql('postgres',
+ "SELECT injection_points_attach('stats-notice', 'notice');");
+$node->safe_psql('postgres', "SELECT injection_points_run('stats-notice');");
+$node->safe_psql('postgres', "SELECT injection_points_run('stats-notice');");
+my $numcalls = $node->safe_psql('postgres',
+ "SELECT injection_points_stats_numcalls('stats-notice');");
+is($numcalls, '2', 'number of stats calls');
+
+# Restart the node cleanly, stats should still be around.
+$node->restart;
+$numcalls = $node->safe_psql('postgres',
+ "SELECT injection_points_stats_numcalls('stats-notice');");
+is($numcalls, '2', 'number of stats after clean restart');
+
+# On crash the stats are gone.
+$node->stop('immediate');
+$node->start;
+$numcalls = $node->safe_psql('postgres',
+ "SELECT injection_points_stats_numcalls('stats-notice');");
+is($numcalls, '', 'number of stats after clean restart');
+
+done_testing();
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 8de9978ad8..48febe4698 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2119,6 +2119,7 @@ PgStatShared_Common
PgStatShared_Database
PgStatShared_Function
PgStatShared_HashEntry
+PgStatShared_InjectionPoint
PgStatShared_IO
PgStatShared_Relation
PgStatShared_ReplSlot
@@ -2150,6 +2151,7 @@ PgStat_Snapshot
PgStat_SnapshotEntry
PgStat_StatDBEntry
PgStat_StatFuncEntry
+PgStat_StatInjEntry
PgStat_StatReplSlotEntry
PgStat_StatSubEntry
PgStat_StatTabEntry
--
2.45.2
From 29774effafad952be4a6e9d6aafc8b0638dbe90d Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@paquier.xyz>
Date: Thu, 18 Jul 2024 14:44:33 +0900
Subject: [PATCH v3 5/5] injection_points: Add example for fixed-numbered
statistics
This acts as a template to show what can be achieved with fixed-numbered
stats (like WAL, bgwriter, etc.) for pluggable cumulative statistics.
---
src/test/modules/injection_points/Makefile | 3 +-
.../injection_points--1.0.sql | 11 +
.../injection_points/injection_points.c | 4 +
.../injection_points/injection_stats.h | 7 +
.../injection_points/injection_stats_fixed.c | 192 ++++++++++++++++++
src/test/modules/injection_points/meson.build | 1 +
.../modules/injection_points/t/001_stats.pl | 11 +-
7 files changed, 227 insertions(+), 2 deletions(-)
create mode 100644 src/test/modules/injection_points/injection_stats_fixed.c
diff --git a/src/test/modules/injection_points/Makefile b/src/test/modules/injection_points/Makefile
index 7b9cd12a2a..ed28cd13a8 100644
--- a/src/test/modules/injection_points/Makefile
+++ b/src/test/modules/injection_points/Makefile
@@ -4,7 +4,8 @@ MODULE_big = injection_points
OBJS = \
$(WIN32RES) \
injection_points.o \
- injection_stats.o
+ injection_stats.o \
+ injection_stats_fixed.o
EXTENSION = injection_points
DATA = injection_points--1.0.sql
PGFILEDESC = "injection_points - facility for injection points"
diff --git a/src/test/modules/injection_points/injection_points--1.0.sql b/src/test/modules/injection_points/injection_points--1.0.sql
index b98d571889..1b2a4938a9 100644
--- a/src/test/modules/injection_points/injection_points--1.0.sql
+++ b/src/test/modules/injection_points/injection_points--1.0.sql
@@ -84,3 +84,14 @@ CREATE FUNCTION injection_points_stats_numcalls(IN point_name TEXT)
RETURNS bigint
AS 'MODULE_PATHNAME', 'injection_points_stats_numcalls'
LANGUAGE C STRICT;
+
+--
+-- injection_points_stats_fixed()
+--
+-- Reports fixed-numbered statistics for injection points.
+CREATE FUNCTION injection_points_stats_fixed(OUT numattach int8,
+ OUT numdetach int8,
+ OUT numrun int8)
+RETURNS record
+AS 'MODULE_PATHNAME', 'injection_points_stats_fixed'
+LANGUAGE C STRICT;
diff --git a/src/test/modules/injection_points/injection_points.c b/src/test/modules/injection_points/injection_points.c
index acec4e95b0..dc02be1bbf 100644
--- a/src/test/modules/injection_points/injection_points.c
+++ b/src/test/modules/injection_points/injection_points.c
@@ -297,6 +297,7 @@ injection_points_attach(PG_FUNCTION_ARGS)
condition.pid = MyProcPid;
}
+ pgstat_report_inj_fixed(1, 0, 0);
InjectionPointAttach(name, "injection_points", function, &condition,
sizeof(InjectionPointCondition));
@@ -342,6 +343,7 @@ injection_points_run(PG_FUNCTION_ARGS)
{
char *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+ pgstat_report_inj_fixed(0, 0, 1);
INJECTION_POINT(name);
PG_RETURN_VOID();
@@ -432,6 +434,7 @@ injection_points_detach(PG_FUNCTION_ARGS)
{
char *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+ pgstat_report_inj_fixed(0, 1, 0);
if (!InjectionPointDetach(name))
elog(ERROR, "could not detach injection point \"%s\"", name);
@@ -459,4 +462,5 @@ _PG_init(void)
return;
pgstat_register_inj();
+ pgstat_register_inj_fixed();
}
diff --git a/src/test/modules/injection_points/injection_stats.h b/src/test/modules/injection_points/injection_stats.h
index 3e99705483..d519f29f83 100644
--- a/src/test/modules/injection_points/injection_stats.h
+++ b/src/test/modules/injection_points/injection_stats.h
@@ -15,9 +15,16 @@
#ifndef INJECTION_STATS
#define INJECTION_STATS
+/* injection_stats.c */
extern void pgstat_register_inj(void);
extern void pgstat_create_inj(const char *name);
extern void pgstat_drop_inj(const char *name);
extern void pgstat_report_inj(const char *name);
+/* injection_stats_fixed.c */
+extern void pgstat_register_inj_fixed(void);
+extern void pgstat_report_inj_fixed(uint32 numattach,
+ uint32 numdetach,
+ uint32 numrun);
+
#endif
diff --git a/src/test/modules/injection_points/injection_stats_fixed.c b/src/test/modules/injection_points/injection_stats_fixed.c
new file mode 100644
index 0000000000..75639328a8
--- /dev/null
+++ b/src/test/modules/injection_points/injection_stats_fixed.c
@@ -0,0 +1,192 @@
+/*--------------------------------------------------------------------------
+ *
+ * injection_stats_fixed.c
+ * Code for fixed-numbered statistics of injection points.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/test/modules/injection_points/injection_stats_fixed.c
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "fmgr.h"
+
+#include "common/hashfn.h"
+#include "funcapi.h"
+#include "injection_stats.h"
+#include "pgstat.h"
+#include "utils/builtins.h"
+#include "utils/pgstat_internal.h"
+
+/* Structures for statistics of injection points, fixed-size */
+typedef struct PgStat_StatInjFixedEntry
+{
+ PgStat_Counter numattach; /* number of points attached */
+ PgStat_Counter numdetach; /* number of points detached */
+ PgStat_Counter numrun; /* number of points run */
+ TimestampTz stat_reset_timestamp;
+} PgStat_StatInjFixedEntry;
+
+typedef struct PgStatShared_InjectionPointFixed
+{
+ LWLock lock; /* protects all the counters */
+ uint32 changecount;
+ PgStat_StatInjFixedEntry stats;
+ PgStat_StatInjFixedEntry reset_offset;
+} PgStatShared_InjectionPointFixed;
+
+/* Callbacks for fixed-numbered stats */
+static void injection_stats_fixed_init_shmem_cb(void *stats);
+static void injection_stats_fixed_reset_all_cb(TimestampTz ts);
+static void injection_stats_fixed_snapshot_cb(void);
+
+static const PgStat_KindInfo injection_stats_fixed = {
+ .name = "injection_points_fixed",
+ .fixed_amount = true,
+
+ .shared_size = sizeof(PgStat_StatInjFixedEntry),
+ .shared_data_off = offsetof(PgStatShared_InjectionPointFixed, stats),
+ .shared_data_len = sizeof(((PgStatShared_InjectionPointFixed *) 0)->stats),
+
+ .init_shmem_cb = injection_stats_fixed_init_shmem_cb,
+ .reset_all_cb = injection_stats_fixed_reset_all_cb,
+ .snapshot_cb = injection_stats_fixed_snapshot_cb,
+};
+
+/*
+ * Kind ID reserved for statistics of injection points.
+ */
+#define PGSTAT_KIND_INJECTION_FIXED 130
+
+/* Track if fixed-numbered stats are loaded */
+static bool inj_fixed_loaded = false;
+
+static void
+injection_stats_fixed_init_shmem_cb(void *stats)
+{
+ PgStatShared_InjectionPointFixed *stats_shmem =
+ (PgStatShared_InjectionPointFixed *) stats;
+
+ LWLockInitialize(&stats_shmem->lock, LWTRANCHE_PGSTATS_DATA);
+}
+
+static void
+injection_stats_fixed_reset_all_cb(TimestampTz ts)
+{
+ PgStatShared_InjectionPointFixed *stats_shmem =
+ pgstat_get_custom_shmem_data(PGSTAT_KIND_INJECTION_FIXED);
+
+ LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
+ pgstat_copy_changecounted_stats(&stats_shmem->reset_offset,
+ &stats_shmem->stats,
+ sizeof(stats_shmem->stats),
+ &stats_shmem->changecount);
+ stats_shmem->stats.stat_reset_timestamp = ts;
+ LWLockRelease(&stats_shmem->lock);
+}
+
+static void
+injection_stats_fixed_snapshot_cb(void)
+{
+ PgStatShared_InjectionPointFixed *stats_shmem =
+ pgstat_get_custom_shmem_data(PGSTAT_KIND_INJECTION_FIXED);
+ PgStat_StatInjFixedEntry *stat_snap =
+ pgstat_get_custom_snapshot_data(PGSTAT_KIND_INJECTION_FIXED);
+ PgStat_StatInjFixedEntry *reset_offset = &stats_shmem->reset_offset;
+ PgStat_StatInjFixedEntry reset;
+
+ pgstat_copy_changecounted_stats(stat_snap,
+ &stats_shmem->stats,
+ sizeof(stats_shmem->stats),
+ &stats_shmem->changecount);
+
+ LWLockAcquire(&stats_shmem->lock, LW_SHARED);
+ memcpy(&reset, reset_offset, sizeof(stats_shmem->stats));
+ LWLockRelease(&stats_shmem->lock);
+
+ /* compensate by reset offsets */
+#define FIXED_COMP(fld) stat_snap->fld -= reset.fld;
+ FIXED_COMP(numattach);
+ FIXED_COMP(numdetach);
+ FIXED_COMP(numrun);
+#undef FIXED_COMP
+}
+
+/*
+ * Workhorse to do the registration work, called in _PG_init().
+ */
+void
+pgstat_register_inj_fixed(void)
+{
+ pgstat_register_kind(PGSTAT_KIND_INJECTION_FIXED, &injection_stats_fixed);
+
+ /* mark stats as loaded */
+ inj_fixed_loaded = true;
+}
+
+/*
+ * Report fixed number of statistics for an injection point.
+ */
+void
+pgstat_report_inj_fixed(uint32 numattach,
+ uint32 numdetach,
+ uint32 numrun)
+{
+ PgStatShared_InjectionPointFixed *stats_shmem;
+
+ /* leave if disabled */
+ if (!inj_fixed_loaded)
+ return;
+
+ stats_shmem = pgstat_get_custom_shmem_data(PGSTAT_KIND_INJECTION_FIXED);
+
+ pgstat_begin_changecount_write(&stats_shmem->changecount);
+ stats_shmem->stats.numattach += numattach;
+ stats_shmem->stats.numdetach += numdetach;
+ stats_shmem->stats.numrun += numrun;
+ pgstat_end_changecount_write(&stats_shmem->changecount);
+}
+
+/*
+ * SQL function returning fixed-numbered statistics for injection points.
+ */
+PG_FUNCTION_INFO_V1(injection_points_stats_fixed);
+Datum
+injection_points_stats_fixed(PG_FUNCTION_ARGS)
+{
+ TupleDesc tupdesc;
+ Datum values[3] = {0};
+ bool nulls[3] = {0};
+ PgStat_StatInjFixedEntry *stats;
+
+ if (!inj_fixed_loaded)
+ PG_RETURN_NULL();
+
+ pgstat_snapshot_fixed(PGSTAT_KIND_INJECTION_FIXED);
+ stats = pgstat_get_custom_snapshot_data(PGSTAT_KIND_INJECTION_FIXED);
+
+ /* Initialise attributes information in the tuple descriptor */
+ tupdesc = CreateTemplateTupleDesc(3);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "numattach",
+ INT8OID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 2, "numdetach",
+ INT8OID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 3, "numrun",
+ INT8OID, -1, 0);
+ BlessTupleDesc(tupdesc);
+
+ values[0] = Int64GetDatum(stats->numattach);
+ values[1] = Int64GetDatum(stats->numdetach);
+ values[2] = Int64GetDatum(stats->numrun);
+ nulls[0] = false;
+ nulls[1] = false;
+ nulls[2] = false;
+
+ /* Returns the record as Datum */
+ PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
+}
diff --git a/src/test/modules/injection_points/meson.build b/src/test/modules/injection_points/meson.build
index a52fe5121e..c9e357f644 100644
--- a/src/test/modules/injection_points/meson.build
+++ b/src/test/modules/injection_points/meson.build
@@ -7,6 +7,7 @@ endif
injection_points_sources = files(
'injection_points.c',
'injection_stats.c',
+ 'injection_stats_fixed.c',
)
if host_system == 'windows'
diff --git a/src/test/modules/injection_points/t/001_stats.pl b/src/test/modules/injection_points/t/001_stats.pl
index 7d5a96e522..e3c69b94ca 100644
--- a/src/test/modules/injection_points/t/001_stats.pl
+++ b/src/test/modules/injection_points/t/001_stats.pl
@@ -31,18 +31,27 @@ $node->safe_psql('postgres', "SELECT injection_points_run('stats-notice');");
my $numcalls = $node->safe_psql('postgres',
"SELECT injection_points_stats_numcalls('stats-notice');");
is($numcalls, '2', 'number of stats calls');
+my $fixedstats = $node->safe_psql('postgres',
+ "SELECT * FROM injection_points_stats_fixed();");
+is($fixedstats, '1|0|2', 'number of fixed stats');
# Restart the node cleanly, stats should still be around.
$node->restart;
$numcalls = $node->safe_psql('postgres',
"SELECT injection_points_stats_numcalls('stats-notice');");
is($numcalls, '2', 'number of stats after clean restart');
+$fixedstats = $node->safe_psql('postgres',
+ "SELECT * FROM injection_points_stats_fixed();");
+is($fixedstats, '1|0|2', 'number of fixed stats after clean restart');
# On crash the stats are gone.
$node->stop('immediate');
$node->start;
$numcalls = $node->safe_psql('postgres',
"SELECT injection_points_stats_numcalls('stats-notice');");
-is($numcalls, '', 'number of stats after clean restart');
+is($numcalls, '', 'number of stats after crash');
+$fixedstats = $node->safe_psql('postgres',
+ "SELECT * FROM injection_points_stats_fixed();");
+is($fixedstats, '0|0|0', 'number of fixed stats after crash');
done_testing();
--
2.45.2
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