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[PATCH v30 02/11] Add relisivm column to pg_class system catalog 171+ messages / 2 participants [nested] [flat]
* [PATCH v30 02/11] Add relisivm column to pg_class system catalog @ 2019-12-20 01:07 Yugo Nagata <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Yugo Nagata @ 2019-12-20 01:07 UTC (permalink / raw) If this boolean column is true, a relations is Incrementally Maintainable Materialized View (IMMV). This is set when IMMV is created. Also, isimmv columns is added to pg_matviews system view. isimmv --- src/backend/catalog/heap.c | 1 + src/backend/catalog/index.c | 1 + src/backend/catalog/system_views.sql | 1 + src/backend/utils/cache/lsyscache.c | 24 ++++++++++++++++++++++++ src/backend/utils/cache/relcache.c | 2 ++ src/include/catalog/pg_class.h | 3 +++ src/include/utils/lsyscache.h | 1 + src/include/utils/rel.h | 2 ++ src/test/regress/expected/rules.out | 1 + 9 files changed, 36 insertions(+) diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c index 348943e36c..b186d9e82c 100644 --- a/src/backend/catalog/heap.c +++ b/src/backend/catalog/heap.c @@ -927,6 +927,7 @@ InsertPgClassTuple(Relation pg_class_desc, values[Anum_pg_class_relrewrite - 1] = ObjectIdGetDatum(rd_rel->relrewrite); values[Anum_pg_class_relfrozenxid - 1] = TransactionIdGetDatum(rd_rel->relfrozenxid); values[Anum_pg_class_relminmxid - 1] = MultiXactIdGetDatum(rd_rel->relminmxid); + values[Anum_pg_class_relisivm - 1] = BoolGetDatum(rd_rel->relisivm); if (relacl != (Datum) 0) values[Anum_pg_class_relacl - 1] = relacl; else diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 4b88a9cb87..3b59c44b0e 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -992,6 +992,7 @@ index_create(Relation heapRelation, indexRelation->rd_rel->relowner = heapRelation->rd_rel->relowner; indexRelation->rd_rel->relam = accessMethodId; indexRelation->rd_rel->relispartition = OidIsValid(parentIndexRelid); + indexRelation->rd_rel->relisivm = false; /* * store index's pg_class entry diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 04227a72d1..273ae3062f 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -146,6 +146,7 @@ CREATE VIEW pg_matviews AS T.spcname AS tablespace, C.relhasindex AS hasindexes, C.relispopulated AS ispopulated, + C.relisivm AS isimmv, pg_get_viewdef(C.oid) AS definition FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace) LEFT JOIN pg_tablespace T ON (T.oid = C.reltablespace) diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c index f730aa26c4..20b873b38e 100644 --- a/src/backend/utils/cache/lsyscache.c +++ b/src/backend/utils/cache/lsyscache.c @@ -2019,6 +2019,30 @@ get_rel_relispartition(Oid relid) return false; } +/* + * get_rel_relisivm + * + * Returns the relisivm flag associated with a given relation. + */ +bool +get_rel_relisivm(Oid relid) +{ + HeapTuple tp; + + tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid)); + if (HeapTupleIsValid(tp)) + { + Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp); + bool result; + + result = reltup->relisivm; + ReleaseSysCache(tp); + return result; + } + else + return false; +} + /* * get_rel_tablespace * diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c index 50acae4529..278b8519b1 100644 --- a/src/backend/utils/cache/relcache.c +++ b/src/backend/utils/cache/relcache.c @@ -1927,6 +1927,8 @@ formrdesc(const char *relationName, Oid relationReltype, /* ... and they're always populated, too */ relation->rd_rel->relispopulated = true; + /* ... and they're always no ivm, too */ + relation->rd_rel->relisivm = false; relation->rd_rel->relreplident = REPLICA_IDENTITY_NOTHING; relation->rd_rel->relpages = 0; diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h index 3b7533e7bb..23a933e46c 100644 --- a/src/include/catalog/pg_class.h +++ b/src/include/catalog/pg_class.h @@ -119,6 +119,9 @@ CATALOG(pg_class,1259,RelationRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(83,Relat /* is relation a partition? */ bool relispartition BKI_DEFAULT(f); + /* is relation a matview with ivm? */ + bool relisivm BKI_DEFAULT(f); + /* link to original rel during table rewrite; otherwise 0 */ Oid relrewrite BKI_DEFAULT(0) BKI_LOOKUP_OPT(pg_class); diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h index e4a200b00e..544fa94a68 100644 --- a/src/include/utils/lsyscache.h +++ b/src/include/utils/lsyscache.h @@ -137,6 +137,7 @@ extern Oid get_rel_namespace(Oid relid); extern Oid get_rel_type_id(Oid relid); extern char get_rel_relkind(Oid relid); extern bool get_rel_relispartition(Oid relid); +extern bool get_rel_relisivm(Oid relid); extern Oid get_rel_tablespace(Oid relid); extern char get_rel_persistence(Oid relid); extern Oid get_transform_fromsql(Oid typid, Oid langid, List *trftypes); diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h index ab9fa4faf9..ae693adaa5 100644 --- a/src/include/utils/rel.h +++ b/src/include/utils/rel.h @@ -675,6 +675,8 @@ RelationCloseSmgr(Relation relation) */ #define RelationIsPopulated(relation) ((relation)->rd_rel->relispopulated) +#define RelationIsIVM(relation) ((relation)->rd_rel->relisivm) + /* * RelationIsAccessibleInLogicalDecoding * True if we need to log enough information to have access via diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 0cd2c64fca..984fe16bb8 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1392,6 +1392,7 @@ pg_matviews| SELECT n.nspname AS schemaname, t.spcname AS tablespace, c.relhasindex AS hasindexes, c.relispopulated AS ispopulated, + c.relisivm AS isimmv, pg_get_viewdef(c.oid) AS definition FROM ((pg_class c LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) -- 2.25.1 --Multipart=_Mon__4_Mar_2024_11_58_46_+0900_UaponF/qQhQrVCFt Content-Type: text/x-diff; name="v30-0003-Allow-to-prolong-life-span-of-transition-tables-.patch" Content-Disposition: attachment; filename="v30-0003-Allow-to-prolong-life-span-of-transition-tables-.patch" Content-Transfer-Encoding: 7bit ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 171+ messages in thread
* [PATCH v1 02/10] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 171+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of sequential scans initiated on tables and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 95 ++++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 7 ++ src/backend/utils/adt/pgstatfuncs.c | 55 ++++++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 4 ++ src/test/regress/expected/stats.out | 10 +++ src/test/regress/sql/stats.sql | 8 +++ 7 files changed, 188 insertions(+) 50.8% doc/src/sgml/ 26.9% src/backend/utils/adt/ 8.0% src/include/catalog/ 7.1% src/test/regress/expected/ 4.0% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..6868af55db4 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,19 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of sequential scans. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1185,72 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>seq_scan</structfield> <type>bigint</type> + </para> + <para> + The number of sequential scans initiated on tables. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5000,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..3ab7802cc5c 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,13 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.seq_scan, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..2adfbdcb65c 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,61 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 3 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->heap_scan); + + if (backend_stats->stat_reset_timestamp != 0) + values[2] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[2] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..e87200374d8 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,timestamptz}', + proargmodes => '{i,o,o,o}', + proargnames => '{pid,pid,seq_scan,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..63f8f12b8a5 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,10 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + seq_scan, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, seq_scan, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..937bf4bfc5b 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -118,6 +118,8 @@ SELECT t.seq_scan, t.seq_tup_read, t.idx_scan, t.idx_tup_fetch, pg_catalog.pg_statio_user_tables AS b WHERE t.relname='tenk2' AND b.relname='tenk2'; COMMIT; +SELECT seq_scan AS seq_scan_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset -- test effects of TRUNCATE on n_live_tup/n_dead_tup counters CREATE TABLE trunc_stats_test(id serial); CREATE TABLE trunc_stats_test1(id serial, stuff text); @@ -219,6 +221,14 @@ SELECT st.seq_scan >= pr.seq_scan + 1, t | t | t | t (1 row) +SELECT seq_scan AS seq_scan_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :seq_scan_after > :seq_scan_before; + ?column? +---------- + t +(1 row) + SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages, st.idx_blks_read + st.idx_blks_hit >= pr.idx_blks + 1 FROM pg_statio_user_tables AS st, pg_class AS cl, prevstats AS pr diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..b743352eadb 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -38,6 +38,9 @@ SELECT t.seq_scan, t.seq_tup_read, t.idx_scan, t.idx_tup_fetch, WHERE t.relname='tenk2' AND b.relname='tenk2'; COMMIT; +SELECT seq_scan AS seq_scan_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + -- test effects of TRUNCATE on n_live_tup/n_dead_tup counters CREATE TABLE trunc_stats_test(id serial); CREATE TABLE trunc_stats_test1(id serial, stuff text); @@ -122,6 +125,11 @@ SELECT st.seq_scan >= pr.seq_scan + 1, FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr WHERE st.relname='tenk2' AND cl.relname='tenk2'; +SELECT seq_scan AS seq_scan_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :seq_scan_after > :seq_scan_before; + SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages, st.idx_blks_read + st.idx_blks_hit >= pr.idx_blks + 1 FROM pg_statio_user_tables AS st, pg_class AS cl, prevstats AS pr -- 2.34.1 --j6dXQ8GCuNzKPBpX Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="v1-0003-Adding-seq_tup_read-to-pg_stat_backend.patch" ^ permalink raw reply [nested|flat] 171+ messages in thread
end of thread, other threads:[~2025-08-09 14:22 UTC | newest] Thread overview: 171+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2019-12-20 01:07 [PATCH v30 02/11] Add relisivm column to pg_class system catalog Yugo Nagata <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v1 02/10] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]>
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