From f3a4855aa5356c7d21f656f37d8799b91ba85b52 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Mon, 8 Jul 2024 13:44:14 +0900 Subject: [PATCH v6 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. --- .../injection_points--1.0.sql | 11 ++ .../injection_points/injection_points.c | 3 + .../injection_points/injection_stats.c | 155 +++++++++++++++++- .../injection_points/injection_stats.h | 3 + .../modules/injection_points/t/001_stats.pl | 11 +- 5 files changed, 180 insertions(+), 3 deletions(-) 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 747a64e812..fa0b1d06ae 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 +74,14 @@ 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 eb411b9d44..f65bd83cc3 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(); @@ -418,6 +420,7 @@ 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); diff --git a/src/test/modules/injection_points/injection_stats.c b/src/test/modules/injection_points/injection_stats.c index c37b0b33d3..69560b7fdc 100644 --- a/src/test/modules/injection_points/injection_stats.c +++ b/src/test/modules/injection_points/injection_stats.c @@ -17,12 +17,13 @@ #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 */ +/* Structures for statistics of injection points, variable-size */ typedef struct PgStat_StatInjEntry { PgStat_Counter numcalls; /* number of times point has been run */ @@ -35,6 +36,9 @@ typedef struct PgStatShared_InjectionPoint } PgStatShared_InjectionPoint; static bool injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait); +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 = { .name = "injection_points", @@ -50,18 +54,51 @@ static const PgStat_KindInfo injection_stats = { .flush_pending_cb = injection_stats_flush_cb, }; +/* 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; + +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, +}; + /* * 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)) #define PGSTAT_KIND_INJECTION PGSTAT_KIND_EXPERIMENTAL +#define PGSTAT_KIND_INJECTION_FIXED (PGSTAT_KIND_EXPERIMENTAL + 1) +/* Position of fixed-numbered data in internal structures */ +#define PGSTAT_KIND_INJECTION_IDX (PGSTAT_KIND_INJECTION_FIXED - PGSTAT_KIND_CUSTOM_MIN) /* Track if stats are loaded */ static bool inj_stats_loaded = false; /* - * Callback for stats handling + * Callbacks for stats handling */ static bool injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait) @@ -79,6 +116,59 @@ injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait) return true; } +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 = + (PgStatShared_InjectionPointFixed *) + pgStatLocal.shmem->custom_data[PGSTAT_KIND_INJECTION_IDX]; + + 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 = + (PgStatShared_InjectionPointFixed *) + pgStatLocal.shmem->custom_data[PGSTAT_KIND_INJECTION_IDX]; + PgStat_StatInjFixedEntry *stat_snap = (PgStat_StatInjFixedEntry *) + pgStatLocal.snapshot.custom_data[PGSTAT_KIND_INJECTION_IDX]; + 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 +} + /* * Support function for the SQL-callable pgstat* functions. Returns * a pointer to the injection point statistics struct. @@ -105,6 +195,7 @@ void pgstat_register_inj(void) { pgstat_register_kind(PGSTAT_KIND_INJECTION, &injection_stats); + pgstat_register_kind(PGSTAT_KIND_INJECTION_FIXED, &injection_stats_fixed); /* mark stats as loaded */ inj_stats_loaded = true; @@ -176,6 +267,30 @@ pgstat_report_inj(const char *name) pgstat_unlock_entry(entry_ref); } +/* + * 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_stats_loaded) + return; + + stats_shmem = (PgStatShared_InjectionPointFixed *) + pgStatLocal.shmem->custom_data[PGSTAT_KIND_INJECTION_IDX]; + + 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 the number of times an injection point * has been called. @@ -192,3 +307,39 @@ injection_points_stats_numcalls(PG_FUNCTION_ARGS) PG_RETURN_INT64(entry->numcalls); } + +/* + * 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; + + pgstat_snapshot_fixed(PGSTAT_KIND_INJECTION_FIXED); + stats = pgStatLocal.snapshot.custom_data[PGSTAT_KIND_INJECTION_IDX]; + + /* 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/injection_stats.h b/src/test/modules/injection_points/injection_stats.h index 3e99705483..cf68b25f7b 100644 --- a/src/test/modules/injection_points/injection_stats.h +++ b/src/test/modules/injection_points/injection_stats.h @@ -19,5 +19,8 @@ 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); +extern void pgstat_report_inj_fixed(uint32 numattach, + uint32 numdetach, + uint32 numrun); #endif 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