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[PATCH v1 02/10] Adding the pg_stat_backend view 325+ messages / 2 participants [nested] [flat]
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v1 02/10] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 0 siblings, 0 replies; 325+ 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] 325+ messages in thread
* [PATCH v44 05/10] Rename ChangeDest to ChangeContext, and absorb IndexInsertState @ 2026-03-23 20:27 Álvaro Herrera <alvherre@kurilemu.de> 0 siblings, 0 replies; 325+ messages in thread From: Álvaro Herrera @ 2026-03-23 20:27 UTC (permalink / raw) This makes the data structure simpler, as we only need a single struct which can be passed down to all functions. Also, the inititalization and release sequences are a bit simpler and there's a single location in charge. --- src/backend/commands/cluster.c | 307 ++++++++++++++----------------- src/tools/pgindent/typedefs.list | 2 +- 2 files changed, 135 insertions(+), 174 deletions(-) diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index b4acaeb6b93..b86e600af41 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -113,15 +113,6 @@ typedef struct static RelFileLocator repacked_rel_locator = {.relNumber = InvalidOid}; static RelFileLocator repacked_rel_toast_locator = {.relNumber = InvalidOid}; -/* - * Everything we need to call ExecInsertIndexTuples(). - */ -typedef struct IndexInsertState -{ - ResultRelInfo *rri; - EState *estate; -} IndexInsertState; - /* The WAL segment being decoded. */ static XLogSegNo repack_current_segment = 0; @@ -134,31 +125,27 @@ static XLogSegNo repack_current_segment = 0; /* * Information needed to apply concurrent data changes. */ -typedef struct ChangeDest +typedef struct ChangeContext { /* The relation the changes are applied to. */ - Relation rel; - - /* - * The following is needed to find the existing tuple if the change is - * UPDATE or DELETE. 'ident_key' should have all the fields except for - * 'sk_argument' initialized. - */ - Relation ident_index; - ScanKey ident_key; - int ident_key_nentries; + Relation cc_rel; /* Needed to update indexes of rel_dst. */ - IndexInsertState *iistate; + ResultRelInfo *cc_rri; + EState *cc_estate; /* - * Sequential number of the file containing the changes. - * - * TODO This field makes the structure name less descriptive. Should we - * rename it, e.g. to ChangeApplyInfo? + * Existing tuples to UPDATE and DELETE are located via this index. We + * keep the scankey in partially initialized state to avoid repeated work. + * sk_argument is completed on the fly. */ - int file_seq; -} ChangeDest; + Relation cc_ident_index; + ScanKey cc_ident_key; + int cc_ident_key_nentries; + + /* Sequential number of the file containing the changes. */ + int cc_file_seq; +} ChangeContext; /* * Layout of shared memory used for communication between backend and the @@ -278,29 +265,27 @@ static bool repack_is_permitted_for_relation(RepackCommand cmd, static LogicalDecodingContext *repack_setup_logical_decoding(Oid relid); static bool decode_concurrent_changes(LogicalDecodingContext *ctx, DecodingWorkerShared *shared); -static void apply_concurrent_changes(BufFile *file, ChangeDest *dest); +static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt); static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot, - IndexInsertState *iistate); + ChangeContext *chgcxt); static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple, TupleTableSlot *ondisk_tuple, - IndexInsertState *iistate); + ChangeContext *chgcxt); static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot); static void restore_tuple(BufFile *file, Relation relation, TupleTableSlot *slot); static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest, - TupleTableSlot *src); -static bool find_target_tuple(Relation rel, ChangeDest *dest, + TupleTableSlot *src); +static bool find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator, TupleTableSlot *received); static void process_concurrent_changes(XLogRecPtr end_of_wal, - ChangeDest *dest, + ChangeContext *chgcxt, bool done); -static IndexInsertState *get_index_insert_state(Relation relation, - Oid ident_index_id, - Relation *ident_index_p); -static ScanKey build_identity_key(Oid ident_idx_oid, Relation rel_src, - int *nentries); -static void free_index_insert_state(IndexInsertState *iistate); +static void initialize_change_context(ChangeContext *chgcxt, + Relation relation, + Oid ident_index_id); +static void release_change_context(ChangeContext *chgcxt); static void cleanup_logical_decoding(LogicalDecodingContext *ctx); static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, Oid identIdx, @@ -2871,13 +2856,13 @@ decode_concurrent_changes(LogicalDecodingContext *ctx, * Apply changes stored in 'file'. */ static void -apply_concurrent_changes(BufFile *file, ChangeDest *dest) +apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt) { - ConcurrentChangeKind kind = '\0'; - Relation rel = dest->rel; - TupleTableSlot *spilled_tuple; - TupleTableSlot *old_update_tuple; - TupleTableSlot *ondisk_tuple; + ConcurrentChangeKind kind = '\0'; + Relation rel = chgcxt->cc_rel; + TupleTableSlot *spilled_tuple; + TupleTableSlot *old_update_tuple; + TupleTableSlot *ondisk_tuple; MemoryContext apply_cxt; bool have_old_tuple = false; @@ -2924,12 +2909,12 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest) /* * Just before an UPDATE or DELETE, we must update the command - * counter, because the change could refer to a tuple that we - * have just inserted; and before an INSERT, we have to do this - * also if the previous command was either update or delete. + * counter, because the change could refer to a tuple that we have + * just inserted; and before an INSERT, we have to do this also if the + * previous command was either update or delete. * - * With this approach we don't spend so many CCIs for long - * strings of only INSERTs, which can't affect one another. + * With this approach we don't spend so many CCIs for long strings of + * only INSERTs, which can't affect one another. */ if (kind == CHANGE_UPDATE_NEW || kind == CHANGE_DELETE || (kind == CHANGE_INSERT && (prevkind == CHANGE_UPDATE_NEW || @@ -2946,22 +2931,22 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest) if (kind == CHANGE_INSERT) { - apply_concurrent_insert(rel, spilled_tuple, dest->iistate); + apply_concurrent_insert(rel, spilled_tuple, chgcxt); } else if (kind == CHANGE_DELETE) { - bool found; + bool found; /* Find the tuple to be deleted */ - found = find_target_tuple(rel, dest, spilled_tuple, ondisk_tuple); + found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple); if (!found) elog(ERROR, "failed to find target tuple"); apply_concurrent_delete(rel, ondisk_tuple); } else if (kind == CHANGE_UPDATE_NEW) { - TupleTableSlot *key; - bool found; + TupleTableSlot *key; + bool found; if (have_old_tuple) key = old_update_tuple; @@ -2969,20 +2954,20 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest) key = spilled_tuple; /* Find the tuple to be updated or deleted. */ - found = find_target_tuple(rel, dest, key, ondisk_tuple); + found = find_target_tuple(rel, chgcxt, key, ondisk_tuple); if (!found) elog(ERROR, "failed to find target tuple"); /* * If 'tup' contains TOAST pointers, they point to the old - * relation's toast. Copy the corresponding TOAST pointers for - * the new relation from the existing tuple. (The fact that we - * received a TOAST pointer here implies that the attribute - * hasn't changed.) + * relation's toast. Copy the corresponding TOAST pointers for the + * new relation from the existing tuple. (The fact that we + * received a TOAST pointer here implies that the attribute hasn't + * changed.) */ adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple); - apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, dest->iistate); + apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt); ExecClearTuple(old_update_tuple); have_old_tuple = false; @@ -3006,7 +2991,7 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest) */ static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot, - IndexInsertState *iistate) + ChangeContext *chgcxt) { List *recheck; @@ -3019,8 +3004,8 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot, * action that already happened, we have no use for the recheck list of * indexes returned, so just free it. XXX or maybe just leave it? */ - recheck = ExecInsertIndexTuples(iistate->rri, - iistate->estate, + recheck = ExecInsertIndexTuples(chgcxt->cc_rri, + chgcxt->cc_estate, 0, slot, NIL, NULL); @@ -3028,7 +3013,7 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot, pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_INSERTED, 1); - ResetPerTupleExprContext(iistate->estate); + ResetPerTupleExprContext(chgcxt->cc_estate); } /* @@ -3038,7 +3023,7 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot, static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple, TupleTableSlot *ondisk_tuple, - IndexInsertState *iistate) + ChangeContext *chgcxt) { LockTupleMode lockmode; TM_FailureData tmfd; @@ -3065,13 +3050,13 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple, if (update_indexes == TU_Summarizing) flags |= EIIT_ONLY_SUMMARIZING; - recheck = ExecInsertIndexTuples(iistate->rri, - iistate->estate, + recheck = ExecInsertIndexTuples(chgcxt->cc_rri, + chgcxt->cc_estate, flags, spilled_tuple, NIL, NULL); list_free(recheck); - ResetPerTupleExprContext(iistate->estate); + ResetPerTupleExprContext(chgcxt->cc_estate); } pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_UPDATED, 1); @@ -3135,19 +3120,19 @@ restore_tuple(BufFile *file, Relation relation, TupleTableSlot *slot) ExecForceStoreHeapTuple(tup, slot, false); /* - * Next, read any attributes we stored separately into the tts_values array - * elements expecting them, if any. This matches store_change. + * Next, read any attributes we stored separately into the tts_values + * array elements expecting them, if any. This matches store_change. */ BufFileReadExact(file, &natt_ext, sizeof(natt_ext)); if (natt_ext > 0) { - TupleDesc desc = slot->tts_tupleDescriptor; + TupleDesc desc = slot->tts_tupleDescriptor; for (int i = 0; i < desc->natts; i++) { CompactAttribute *attr = TupleDescCompactAttr(desc, i); - varlena *varlen; - alignas(uint32) varlena varhdr; + varlena *varlen; + alignas(uint32) varlena varhdr; void *value; Size varlensz; @@ -3219,10 +3204,10 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s * not found, return false. */ static bool -find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator, +find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator, TupleTableSlot *retrieved) { - Form_pg_index idx = dest->ident_index->rd_index; + Form_pg_index idx = chgcxt->cc_ident_index->rd_index; IndexScanDesc scan; bool retval; @@ -3233,9 +3218,9 @@ find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator, * * Use the incoming tuple to finalize the scan key. */ - for (int i = 0; i < dest->ident_key_nentries; i++) + for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++) { - ScanKey entry = &dest->ident_key[i]; + ScanKey entry = &chgcxt->cc_ident_key[i]; AttrNumber attno = idx->indkey.values[i]; entry->sk_argument = locator->tts_values[attno - 1]; @@ -3243,9 +3228,9 @@ find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator, } /* XXX no instrumentation for now */ - scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(), - NULL, dest->ident_key_nentries, 0); - index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0); + scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(), + NULL, chgcxt->cc_ident_key_nentries, 0); + index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0); retval = index_getnext_slot(scan, ForwardScanDirection, retrieved); index_endscan(scan); @@ -3260,7 +3245,7 @@ find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator, * are far too similar to each other. */ static void -process_concurrent_changes(XLogRecPtr end_of_wal, ChangeDest *dest, bool done) +process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool done) { DecodingWorkerShared *shared; char fname[MAXPGPATH]; @@ -3293,7 +3278,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeDest *dest, bool done) /* * Has the worker exported the file we are waiting for? */ - if (last_exported == dest->file_seq) + if (last_exported == chgcxt->cc_file_seq) break; ConditionVariableSleep(&shared->cv, WAIT_EVENT_REPACK_WORKER_EXPORT); @@ -3301,117 +3286,99 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeDest *dest, bool done) ConditionVariableCancelSleep(); /* Open the file. */ - DecodingWorkerFileName(fname, shared->relid, dest->file_seq); + DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq); file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false); - apply_concurrent_changes(file, dest); + apply_concurrent_changes(file, chgcxt); BufFileClose(file); /* Get ready for the next file. */ - dest->file_seq++; + chgcxt->cc_file_seq++; } /* - * Initialize IndexInsertState for index specified by ident_index_id. - * - * While doing that, also return the identity index in *ident_index_p. + * Initialize the ChangeContext struct for the given relation, with + * the given index as identity index. */ -static IndexInsertState * -get_index_insert_state(Relation relation, Oid ident_index_id, - Relation *ident_index_p) +static void +initialize_change_context(ChangeContext *chgcxt, + Relation relation, Oid ident_index_id) { - EState *estate; - IndexInsertState *result; - Relation ident_index = NULL; + chgcxt->cc_rel = relation; - result = (IndexInsertState *) palloc0(sizeof(IndexInsertState)); - estate = CreateExecutorState(); + /* Only initialize fields needed by ExecInsertIndexTuples(). */ + chgcxt->cc_estate = CreateExecutorState(); - result->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo)); - InitResultRelInfo(result->rri, relation, 0, 0, 0); - ExecOpenIndices(result->rri, false); + chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo)); + InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0); + ExecOpenIndices(chgcxt->cc_rri, false); /* - * Find the relcache entry of the identity index so that we spend no extra - * effort to open / close it. + * The table's relcache entry already has the relcache entry for the + * identity index; find that. */ - for (int i = 0; i < result->rri->ri_NumIndices; i++) + chgcxt->cc_ident_index = NULL; + for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++) { Relation ind_rel; - ind_rel = result->rri->ri_IndexRelationDescs[i]; + ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i]; if (ind_rel->rd_id == ident_index_id) - ident_index = ind_rel; + { + chgcxt->cc_ident_index = ind_rel; + break; + } } - if (ident_index == NULL) + if (chgcxt->cc_ident_index == NULL) elog(ERROR, "failed to find identity index"); - /* Only initialize fields needed by ExecInsertIndexTuples(). */ - result->estate = estate; - - *ident_index_p = ident_index; - return result; -} - -/* - * Build scan key to process logical changes. - */ -static ScanKey -build_identity_key(Oid ident_idx_oid, Relation rel_src, int *nentries) -{ - Relation ident_idx_rel; - Form_pg_index ident_idx; - int n, - i; - ScanKey result; - - Assert(OidIsValid(ident_idx_oid)); - ident_idx_rel = index_open(ident_idx_oid, AccessShareLock); - ident_idx = ident_idx_rel->rd_index; - n = ident_idx->indnkeyatts; - result = (ScanKey) palloc(sizeof(ScanKeyData) * n); - for (i = 0; i < n; i++) + /* Set up for scanning said identity index */ { - ScanKey entry; - Oid opfamily, - opcintype, - opno, - opcode; + Form_pg_index indexForm; - entry = &result[i]; + indexForm = chgcxt->cc_ident_index->rd_index; + chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts; + chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts); + for (int i = 0; i < indexForm->indnkeyatts; i++) + { + ScanKey entry; + Oid opfamily, + opcintype, + opno, + opcode; - opfamily = ident_idx_rel->rd_opfamily[i]; - opcintype = ident_idx_rel->rd_opcintype[i]; - opno = get_opfamily_member(opfamily, opcintype, opcintype, - BTEqualStrategyNumber); + entry = &chgcxt->cc_ident_key[i]; - if (!OidIsValid(opno)) - elog(ERROR, "failed to find = operator for type %u", opcintype); + opfamily = chgcxt->cc_ident_index->rd_opfamily[i]; + opcintype = chgcxt->cc_ident_index->rd_opcintype[i]; + opno = get_opfamily_member(opfamily, opcintype, opcintype, + BTEqualStrategyNumber); + if (!OidIsValid(opno)) + elog(ERROR, "failed to find = operator for type %u", opcintype); + opcode = get_opcode(opno); + if (!OidIsValid(opcode)) + elog(ERROR, "failed to find = operator for operator %u", opno); - opcode = get_opcode(opno); - if (!OidIsValid(opcode)) - elog(ERROR, "failed to find = operator for operator %u", opno); - - /* Initialize everything but argument. */ - ScanKeyInit(entry, - i + 1, - BTEqualStrategyNumber, opcode, - (Datum) NULL); - entry->sk_collation = ident_idx_rel->rd_indcollation[i]; + /* Initialize everything but argument. */ + ScanKeyInit(entry, + i + 1, + BTEqualStrategyNumber, opcode, + (Datum) NULL); + entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i]; + } } - index_close(ident_idx_rel, AccessShareLock); - *nentries = n; - return result; + chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1; } static void -free_index_insert_state(IndexInsertState *iistate) +release_change_context(ChangeContext *chgcxt) { - ExecCloseIndices(iistate->rri); - FreeExecutorState(iistate->estate); - pfree(iistate->rri); - pfree(iistate); + ExecCloseIndices(chgcxt->cc_rri); + FreeExecutorState(chgcxt->cc_estate); + /* XXX are these pfrees necessary? */ + pfree(chgcxt->cc_rri); + pfree(chgcxt->cc_ident_key); } static void @@ -3450,7 +3417,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, Relation *ind_refs, *ind_refs_p; int nind; - ChangeDest chgdst; + ChangeContext chgcxt; /* Like in cluster_rel(). */ lockmode_old = ShareUpdateExclusiveLock; @@ -3496,12 +3463,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, errmsg("identity index missing on the new relation")); /* Gather information to apply concurrent changes. */ - chgdst.rel = NewHeap; - chgdst.iistate = get_index_insert_state(NewHeap, ident_idx_new, - &chgdst.ident_index); - chgdst.ident_key = build_identity_key(ident_idx_new, OldHeap, - &chgdst.ident_key_nentries); - chgdst.file_seq = WORKER_FILE_SNAPSHOT + 1; + initialize_change_context(&chgcxt, NewHeap, ident_idx_new); /* * During testing, wait for another backend to perform concurrent data @@ -3523,7 +3485,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, * hold AccessExclusiveLock. (Quite some amount of WAL could have been * written during the data copying and index creation.) */ - process_concurrent_changes(end_of_wal, &chgdst, false); + process_concurrent_changes(end_of_wal, &chgcxt, false); /* * Acquire AccessExclusiveLock on the table, its TOAST relation (if there @@ -3608,7 +3570,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, * Apply the concurrent changes again. Indicate that the decoding worker * won't be needed anymore. */ - process_concurrent_changes(end_of_wal, &chgdst, true); + process_concurrent_changes(end_of_wal, &chgcxt, true); /* Remember info about rel before closing OldHeap */ relpersistence = OldHeap->rd_rel->relpersistence; @@ -3659,8 +3621,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, table_close(NewHeap, NoLock); /* Cleanup what we don't need anymore. (And close the identity index.) */ - pfree(chgdst.ident_key); - free_index_insert_state(chgdst.iistate); + release_change_context(&chgcxt); /* * Swap the relations and their TOAST relations and TOAST indexes. This @@ -3980,7 +3941,7 @@ repack_worker_internal(dsm_segment *seg) for (;;) { - bool stop = decode_concurrent_changes(decoding_ctx, shared); + bool stop = decode_concurrent_changes(decoding_ctx, shared); if (stop) break; diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 72f7c0b992b..12bfd50d25b 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -426,7 +426,7 @@ CatCacheHeader CatalogId CatalogIdMapEntry CatalogIndexState -ChangeDest +ChangeContext ChangeVarNodes_callback ChangeVarNodes_context ChannelName -- 2.47.3 --gwom7bl7ogtszo4k Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v44-0006-rename-routines-on-the-logical-output-plugin-sid.patch" ^ permalink raw reply [nested|flat] 325+ messages in thread
end of thread, other threads:[~2026-03-23 20:27 UTC | newest] Thread overview: 325+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 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<bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the 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Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v1 02/10] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <bertranddrouvot.pg@gmail.com> 2026-03-23 20:27 [PATCH v44 05/10] Rename ChangeDest to ChangeContext, and absorb IndexInsertState Álvaro Herrera <alvherre@kurilemu.de>
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