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[PATCH v4 3/3] Replace matview WITH OLD DATA 122+ messages / 2 participants [nested] [flat]
* [PATCH v4 3/3] Replace matview WITH OLD DATA @ 2024-07-26 21:33 Erik Wienhold <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Erik Wienhold @ 2024-07-26 21:33 UTC (permalink / raw) --- .../sgml/ref/create_materialized_view.sgml | 16 +++++++++-- src/backend/commands/createas.c | 26 +++++++++++------ src/backend/parser/gram.y | 16 +++++++++++ src/include/nodes/primnodes.h | 1 + src/test/regress/expected/matview.out | 28 +++++++++++++++++++ src/test/regress/sql/matview.sql | 15 ++++++++++ 6 files changed, 90 insertions(+), 12 deletions(-) diff --git a/doc/src/sgml/ref/create_materialized_view.sgml b/doc/src/sgml/ref/create_materialized_view.sgml index 5e03320eb7..1352e9de40 100644 --- a/doc/src/sgml/ref/create_materialized_view.sgml +++ b/doc/src/sgml/ref/create_materialized_view.sgml @@ -27,7 +27,7 @@ CREATE [ OR REPLACE ] MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_nam [ WITH ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ] [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ] AS <replaceable>query</replaceable> - [ WITH [ NO ] DATA ] + [ WITH [ NO | OLD ] DATA ] </synopsis> </refsynopsisdiv> @@ -37,7 +37,8 @@ CREATE [ OR REPLACE ] MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_nam <para> <command>CREATE MATERIALIZED VIEW</command> defines a materialized view of a query. The query is executed and used to populate the view at the time - the command is issued (unless <command>WITH NO DATA</command> is used) and may be + the command is issued (unless <command>WITH NO DATA</command> or + <command>WITH OLD DATA</command> is used) and may be refreshed later using <command>REFRESH MATERIALIZED VIEW</command>. </para> @@ -162,7 +163,7 @@ CREATE [ OR REPLACE ] MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_nam </varlistentry> <varlistentry> - <term><literal>WITH [ NO ] DATA</literal></term> + <term><literal>WITH [ NO | OLD ] DATA</literal></term> <listitem> <para> This clause specifies whether or not the materialized view should be @@ -170,6 +171,15 @@ CREATE [ OR REPLACE ] MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_nam flagged as unscannable and cannot be queried until <command>REFRESH MATERIALIZED VIEW</command> is used. </para> + + <para> + The form <command>WITH OLD DATA</command> keeps the already stored data + when replacing an existing materialized view to keep it populated. For + newly created materialized views, this has the same effect as + <command>WITH DATA</command>. Use this form if you want to use + <command>REFRESH MATERIALIZED VIEW CONCURRENTLY</command> as it requires + a populated materialized view. + </para> </listitem> </varlistentry> diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c index d4bc5e5c08..8db000554c 100644 --- a/src/backend/commands/createas.c +++ b/src/backend/commands/createas.c @@ -332,18 +332,26 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt, /* An existing materialized view can be replaced. */ if (is_matview && into->replace) { - RefreshMatViewStmt *refresh; - /* Change the relation to match the new query and other options. */ - (void) create_ctas_nodata(query->targetList, into); + address = create_ctas_nodata(query->targetList, into); - /* Refresh the materialized view with a fake statement. */ - refresh = makeNode(RefreshMatViewStmt); - refresh->relation = into->rel; - refresh->skipData = into->skipData; - refresh->concurrent = false; + /* + * Refresh the materialized view with a fake statement unless we + * must keep the old data. + */ + if (!into->keepData) + { + RefreshMatViewStmt *refresh; + + refresh = makeNode(RefreshMatViewStmt); + refresh->relation = into->rel; + refresh->skipData = into->skipData; + refresh->concurrent = false; + + address = ExecRefreshMatView(refresh, NULL, NULL); + } - return ExecRefreshMatView(refresh, NULL, NULL); + return address; } return InvalidObjectAddress; diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index dadc6b630a..1be1a95cd9 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -4838,6 +4838,22 @@ CreateMatViewStmt: $7->replace = true; $$ = (Node *) ctas; } + | CREATE OR REPLACE OptNoLog MATERIALIZED VIEW create_mv_target AS SelectStmt WITH OLD DATA_P + { + CreateTableAsStmt *ctas = makeNode(CreateTableAsStmt); + + ctas->query = $9; + ctas->into = $7; + ctas->objtype = OBJECT_MATVIEW; + ctas->is_select_into = false; + ctas->if_not_exists = false; + /* cram additional flags into the IntoClause */ + $7->rel->relpersistence = $4; + $7->skipData = false; + $7->keepData = true; + $7->replace = true; + $$ = (Node *) ctas; + } ; create_mv_target: diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h index 533fa847ab..6fa3291c64 100644 --- a/src/include/nodes/primnodes.h +++ b/src/include/nodes/primnodes.h @@ -168,6 +168,7 @@ typedef struct IntoClause /* materialized view's SELECT query */ struct Query *viewQuery pg_node_attr(query_jumble_ignore); bool skipData; /* true for WITH NO DATA */ + bool keepData; /* true for WITH OLD DATA */ bool replace; /* replace existing matview? */ } IntoClause; diff --git a/src/test/regress/expected/matview.out b/src/test/regress/expected/matview.out index cefd0d442c..47dfd88bff 100644 --- a/src/test/regress/expected/matview.out +++ b/src/test/regress/expected/matview.out @@ -751,6 +751,23 @@ SELECT * FROM mvtest_replace; 3 (1 row) +-- replace query but keep old data +CREATE OR REPLACE MATERIALIZED VIEW mvtest_replace AS + SELECT 5 AS a + WITH OLD DATA; +SELECT * FROM mvtest_replace; + a +--- + 3 +(1 row) + +REFRESH MATERIALIZED VIEW mvtest_replace; +SELECT * FROM mvtest_replace; + a +--- + 5 +(1 row) + -- add column CREATE OR REPLACE MATERIALIZED VIEW mvtest_replace AS SELECT 4 AS a, 1 b; @@ -905,3 +922,14 @@ ERROR: syntax error at or near "NOT" LINE 1: CREATE OR REPLACE MATERIALIZED VIEW IF NOT EXISTS mvtest_rep... ^ DROP MATERIALIZED VIEW mvtest_replace; +-- Create new matview WITH OLD DATA. This populates the new matview as if +-- WITH DATA had been specified. +CREATE OR REPLACE MATERIALIZED VIEW mvtest_replace AS + SELECT 17 AS a + WITH OLD DATA; +SELECT * FROM mvtest_replace; + a +---- + 17 +(1 row) + diff --git a/src/test/regress/sql/matview.sql b/src/test/regress/sql/matview.sql index c12f0243c9..b268237c24 100644 --- a/src/test/regress/sql/matview.sql +++ b/src/test/regress/sql/matview.sql @@ -338,6 +338,14 @@ SELECT * FROM mvtest_replace; -- error: not populated REFRESH MATERIALIZED VIEW mvtest_replace; SELECT * FROM mvtest_replace; +-- replace query but keep old data +CREATE OR REPLACE MATERIALIZED VIEW mvtest_replace AS + SELECT 5 AS a + WITH OLD DATA; +SELECT * FROM mvtest_replace; +REFRESH MATERIALIZED VIEW mvtest_replace; +SELECT * FROM mvtest_replace; + -- add column CREATE OR REPLACE MATERIALIZED VIEW mvtest_replace AS SELECT 4 AS a, 1 b; @@ -422,3 +430,10 @@ CREATE OR REPLACE MATERIALIZED VIEW IF NOT EXISTS mvtest_replace AS SELECT 1 AS a; DROP MATERIALIZED VIEW mvtest_replace; + +-- Create new matview WITH OLD DATA. This populates the new matview as if +-- WITH DATA had been specified. +CREATE OR REPLACE MATERIALIZED VIEW mvtest_replace AS + SELECT 17 AS a + WITH OLD DATA; +SELECT * FROM mvtest_replace; -- 2.47.0 --hht4bymbvbva5al5-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v3 3/3] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view displays one row per server process, showing statistics related to the current activity of that process. It currently displays the pid, the number of XIDs generated, the number of commits, the number of rollbacks and the time at which these statistics were last reset. It's built on top of a new function (pg_stat_get_backend_statistics()). The idea is the same as pg_stat_activity and pg_stat_get_activity(). Adding documentation and tests. XXX: Bump catversion --- doc/src/sgml/monitoring.sgml | 115 +++++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 9 +++ src/backend/utils/adt/pgstatfuncs.c | 57 +++++++++++++ src/include/catalog/pg_proc.dat | 9 +++ src/test/regress/expected/rules.out | 6 ++ src/test/regress/expected/stats.out | 17 ++++ src/test/regress/sql/stats.sql | 10 +++ 7 files changed, 223 insertions(+) 51.1% doc/src/sgml/ 3.2% src/backend/catalog/ 23.9% src/backend/utils/adt/ 7.2% src/include/catalog/ 9.4% src/test/regress/expected/ 4.9% src/test/regress/sql/ diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3f4a27a736e..0146c812b40 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -320,6 +320,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </entry> </row> + <row> + <entry> + <structname>pg_stat_backend</structname> + <indexterm><primary>pg_stat_backend</primary></indexterm> + </entry> + <entry> + One row per server process, showing statistics related to + the current activity of that process, such as number of commits and + rollbacks. + See <link linkend="monitoring-pg-stat-backend-view"> + <structname>pg_stat_backend</structname></link> for details. + </entry> + </row> + <row> <entry><structname>pg_stat_replication</structname><indexterm><primary>pg_stat_replication</primary></indexterm></entry> <entry>One row per WAL sender process, showing statistics about @@ -1172,6 +1186,91 @@ description | Waiting for a newly initialized WAL file to reach durable storage </note> </sect2> + <sect2 id="monitoring-pg-stat-backend-view"> + <title><structname>pg_stat_backend</structname></title> + + <indexterm> + <primary>pg_stat_backend</primary> + </indexterm> + + <para> + The <structname>pg_stat_backend</structname> view will have one row + per server process, showing statistics related to + the current activity of that process. + </para> + + <table id="pg-stat-backend-view" xreflabel="pg_stat_backend"> + <title><structname>pg_stat_backend</structname> View</title> + <tgroup cols="1"> + <thead> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + Column Type + </para> + <para> + Description + </para></entry> + </row> + </thead> + + <tbody> + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>pid</structfield> <type>integer</type> + </para> + <para> + Process ID of this backend + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xid_count</structfield> <type>bigint</type> + </para> + <para> + The number of XID that have been generated by the backend. It does not take + into account virtual transaction ID on purpose. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_commit</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been committed. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>xact_rollback</structfield> <type>bigint</type> + </para> + <para> + The number of transactions that have been rolled back. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>stats_reset</structfield> <type>timestamp with time zone</type> + </para> + <para> + Time at which these statistics were last reset + </para></entry> + </row> + </tbody> + </tgroup> + </table> + + <note> + <para> + The view does not return statistics for the checkpointer, + the background writer, the startup process and the autovacuum launcher. + </para> + </note> + </sect2> + <sect2 id="monitoring-pg-stat-replication-view"> <title><structname>pg_stat_replication</structname></title> @@ -4921,6 +5020,22 @@ description | Waiting for a newly initialized WAL file to reach durable storage </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>pg_stat_get_backend_statistics</primary> + </indexterm> + <function>pg_stat_get_backend_statistics</function> ( <type>integer</type> ) + <returnvalue>setof record</returnvalue> + </para> + <para> + Returns a record of statistics bout the backend with the specified + process ID, or one record for each active backend in the system + if <literal>NULL</literal> is specified. The fields returned are a + subset of those in the <structname>pg_stat_backend</structname> view. + </para></entry> + </row> + <row> <entry id="pg-stat-get-backend-wal" role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 1b3c5a55882..96a1a556773 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -911,6 +911,15 @@ CREATE VIEW pg_stat_activity AS LEFT JOIN pg_database AS D ON (S.datid = D.oid) LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid); +CREATE VIEW pg_stat_backend AS + SELECT + S.pid, + S.xid_count, + S.xact_commit, + S.xact_rollback, + S.stats_reset + FROM pg_stat_get_backend_statistics(NULL) AS S; + CREATE VIEW pg_stat_replication AS SELECT S.pid, diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index c756c2bebaa..dcb20009bec 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -685,6 +685,63 @@ pg_stat_get_activity(PG_FUNCTION_ARGS) return (Datum) 0; } +/* + * Returns statistics of PG backends. + */ +Datum +pg_stat_get_backend_statistics(PG_FUNCTION_ARGS) +{ +#define PG_STAT_GET_BACKEND_STATS_COLS 5 + int num_backends = pgstat_fetch_stat_numbackends(); + int curr_backend; + int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + + InitMaterializedSRF(fcinfo, 0); + + /* 1-based index */ + for (curr_backend = 1; curr_backend <= num_backends; curr_backend++) + { + /* for each row */ + Datum values[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + bool nulls[PG_STAT_GET_BACKEND_STATS_COLS] = {0}; + LocalPgBackendStatus *local_beentry; + PgBackendStatus *beentry; + PgStat_Backend *backend_stats; + + /* Get the next one in the list */ + local_beentry = pgstat_get_local_beentry_by_index(curr_backend); + beentry = &local_beentry->backendStatus; + + /* If looking for specific PID, ignore all the others */ + if (pid != -1 && beentry->st_procpid != pid) + continue; + + backend_stats = pgstat_fetch_stat_backend_by_pid(beentry->st_procpid, NULL); + + values[0] = Int32GetDatum(beentry->st_procpid); + + if (!backend_stats) + continue; + + values[1] = Int64GetDatum(backend_stats->xid_count); + values[2] = Int64GetDatum(backend_stats->xact_commit); + values[3] = Int64GetDatum(backend_stats->xact_rollback); + + if (backend_stats->stat_reset_timestamp != 0) + values[4] = TimestampTzGetDatum(backend_stats->stat_reset_timestamp); + else + nulls[4] = true; + + tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); + + /* If only a single backend was requested, and we found it, break. */ + if (pid != -1) + break; + } + + return (Datum) 0; +} Datum pg_backend_pid(PG_FUNCTION_ARGS) diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..dc0c0db6358 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5641,6 +5641,15 @@ proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}', prosrc => 'pg_stat_get_activity' }, +{ oid => '9555', + descr => 'statistics: statistics about currently active backends', + proname => 'pg_stat_get_backend_statistics', prorows => '100', proisstrict => 'f', + proretset => 't', provolatile => 's', proparallel => 'r', + prorettype => 'record', proargtypes => 'int4', + proallargtypes => '{int4,int4,int8,int8,int8,timestamptz}', + proargmodes => '{i,o,o,o,o,o}', + proargnames => '{pid,pid,xid_count,xact_commit,xact_rollback,stats_reset}', + prosrc => 'pg_stat_get_backend_statistics' }, { oid => '6318', descr => 'describe wait events', proname => 'pg_get_wait_events', procost => '10', prorows => '250', proretset => 't', provolatile => 'v', prorettype => 'record', diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 35e8aad7701..a107f6ca44d 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1847,6 +1847,12 @@ pg_stat_archiver| SELECT archived_count, last_failed_time, stats_reset FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset); +pg_stat_backend| SELECT pid, + xid_count, + xact_commit, + xact_rollback, + stats_reset + FROM pg_stat_get_backend_statistics(NULL::integer) s(pid, xid_count, xact_commit, xact_rollback, stats_reset); pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean, pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean, pg_stat_get_buf_alloc() AS buffers_alloc, diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out index 605f5070376..a4b6d27c31d 100644 --- a/src/test/regress/expected/stats.out +++ b/src/test/regress/expected/stats.out @@ -135,11 +135,28 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); + pg_stat_force_next_flush +-------------------------- + +(1 row) + +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset +SELECT :xact_commit_after > :xact_commit_before; + ?column? +---------- + t +(1 row) + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql index 54e72866344..f25368d1d25 100644 --- a/src/test/regress/sql/stats.sql +++ b/src/test/regress/sql/stats.sql @@ -58,12 +58,22 @@ INSERT INTO trunc_stats_test1 DEFAULT VALUES; UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2); DELETE FROM trunc_stats_test1 WHERE id = 3; +-- in passing, check that backend's commit is incrementing +SELECT xact_commit AS xact_commit_before + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + BEGIN; UPDATE trunc_stats_test1 SET id = id + 100; TRUNCATE trunc_stats_test1; INSERT INTO trunc_stats_test1 DEFAULT VALUES; COMMIT; +SELECT pg_stat_force_next_flush(); +SELECT xact_commit AS xact_commit_after + FROM pg_stat_backend WHERE pid = pg_backend_pid() \gset + +SELECT :xact_commit_after > :xact_commit_before; + -- use a savepoint: 1 insert, 1 live BEGIN; INSERT INTO trunc_stats_test2 DEFAULT VALUES; -- 2.34.1 --u6+Li7FU79Mt/lVd-- ^ permalink raw reply [nested|flat] 122+ messages in thread
* [PATCH v1 02/10] Adding the pg_stat_backend view @ 2025-08-09 14:22 Bertrand Drouvot <[email protected]> 0 siblings, 0 replies; 122+ messages in thread From: Bertrand Drouvot @ 2025-08-09 14:22 UTC (permalink / raw) This view 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] 122+ messages in thread
end of thread, other threads:[~2025-08-09 14:22 UTC | newest] Thread overview: 122+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2024-07-26 21:33 [PATCH v4 3/3] Replace matview WITH OLD DATA Erik Wienhold <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v1 02/10] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]> 2025-08-09 14:22 [PATCH v3 3/3] Adding the pg_stat_backend view Bertrand Drouvot <[email protected]>
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