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Sergey Dudoladov
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Add pg_stat_session
Author: Sergey Dudoladov Reviewed-by: Discussion: https://www.postgresql.org/message-id/flat/CA%2BFpmFcJF0vwi-SWW0wYO-c-FbhyawLq4tCpRDCJJ8Bq%3Dja-gA%40mail.gmail.com
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‎doc/src/sgml/monitoring.sgml‎

Lines changed: 153 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -414,6 +414,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
414414
See <xref linkend='copy-progress-reporting'/>.
415415
</entry>
416416
</row>
417+
418+
<row>
419+
<entry>
420+
<structname>pg_stat_session</structname>
421+
<indexterm><primary>pg_stat_session</primary></indexterm>
422+
</entry>
423+
<entry>
424+
One row per server process, showing information related to
425+
the currently accumulated activity of that process, such as time spent in
426+
a certain state.
427+
See <link linkend="monitoring-pg-stat-session-view">
428+
<structname>pg_stat_session</structname></link> for details.
429+
</entry>
430+
</row>
417431
</tbody>
418432
</tgroup>
419433
</table>
@@ -5289,6 +5303,129 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
52895303
</tgroup>
52905304
</table>
52915305

5306+
<table id="monitoring-pg-stat-session-view" xreflabel="pg_stat_session">
5307+
<title><structname>pg_stat_session</structname> View</title>
5308+
<tgroup cols="1">
5309+
<thead>
5310+
<row>
5311+
<entry role="catalog_table_entry"><para role="column_definition">
5312+
Column Type
5313+
</para>
5314+
<para>
5315+
Description
5316+
</para></entry>
5317+
</row>
5318+
</thead>
5319+
5320+
<tbody>
5321+
<row>
5322+
<entry role="catalog_table_entry"><para role="column_definition">
5323+
<structfield>pid</structfield> <type>integer</type>
5324+
</para>
5325+
<para>
5326+
Process ID of this backend.
5327+
</para></entry>
5328+
</row>
5329+
5330+
<row>
5331+
<entry role="catalog_table_entry"><para role="column_definition">
5332+
<structfield>total_running_time</structfield> <type>double precision</type>
5333+
</para>
5334+
<para>
5335+
Time in milliseconds this backend spent in the <literal>running</literal> state.
5336+
</para></entry>
5337+
</row>
5338+
5339+
<row>
5340+
<entry role="catalog_table_entry"><para role="column_definition">
5341+
<structfield>total_running_count</structfield> <type>bigint</type>
5342+
</para>
5343+
<para>
5344+
Number of times this backend switched to the <literal>running</literal> state.
5345+
</para></entry>
5346+
</row>
5347+
5348+
<row>
5349+
<entry role="catalog_table_entry"><para role="column_definition">
5350+
<structfield>total_idle_time</structfield> <type>double precision</type>
5351+
</para>
5352+
<para>
5353+
Time in milliseconds this backend spent in the <literal>idle</literal> state.
5354+
</para></entry>
5355+
</row>
5356+
5357+
<row>
5358+
<entry role="catalog_table_entry"><para role="column_definition">
5359+
<structfield>total_idle_count</structfield> <type>bigint</type>
5360+
</para>
5361+
<para>
5362+
Number of times this backend switched to the <literal>idle</literal> state.
5363+
</para></entry>
5364+
</row>
5365+
5366+
<row>
5367+
<entry role="catalog_table_entry"><para role="column_definition">
5368+
<structfield>total_transaction_idle_time</structfield> <type>double precision</type>
5369+
</para>
5370+
<para>
5371+
Time in milliseconds this backend spent in the <literal>idle in transaction</literal>
5372+
state.
5373+
</para></entry>
5374+
</row>
5375+
5376+
<row>
5377+
<entry role="catalog_table_entry"><para role="column_definition">
5378+
<structfield>total_transaction_idle_count</structfield> <type>bigint</type>
5379+
</para>
5380+
<para>
5381+
Number of times this backend switched to the <literal>idle in transaction</literal>
5382+
state.
5383+
</para></entry>
5384+
</row>
5385+
5386+
<row>
5387+
<entry role="catalog_table_entry"><para role="column_definition">
5388+
<structfield>total_transaction_idle_aborted_time</structfield> <type>double precision</type>
5389+
</para>
5390+
<para>
5391+
Time in milliseconds this backend spent in the <literal>idle in transaction (aborted)</literal>
5392+
state.
5393+
</para></entry>
5394+
</row>
5395+
5396+
<row>
5397+
<entry role="catalog_table_entry"><para role="column_definition">
5398+
<structfield>total_transaction_idle_aborted_count</structfield> <type>bigint</type>
5399+
</para>
5400+
<para>
5401+
Number of times this backend switched to the <literal>idle in transaction (aborted)</literal>
5402+
state.
5403+
</para></entry>
5404+
</row>
5405+
5406+
<row>
5407+
<entry role="catalog_table_entry"><para role="column_definition">
5408+
<structfield>total_fastpath_time</structfield> <type>double precision</type>
5409+
</para>
5410+
<para>
5411+
Time in milliseconds this backend spent in the <literal>fastpath</literal> state.
5412+
</para></entry>
5413+
</row>
5414+
5415+
<row>
5416+
<entry role="catalog_table_entry"><para role="column_definition">
5417+
<structfield>total_fastpath_count</structfield> <type>bigint</type>
5418+
</para>
5419+
<para>
5420+
Number of times this backend switched to the <literal>fastpath</literal>
5421+
state.
5422+
</para></entry>
5423+
</row>
5424+
5425+
</tbody>
5426+
</tgroup>
5427+
</table>
5428+
52925429
</sect2>
52935430

52945431
<sect2 id="monitoring-stats-functions">
@@ -5356,6 +5493,22 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
53565493
</para></entry>
53575494
</row>
53585495

5496+
<row>
5497+
<entry role="func_table_entry"><para role="func_signature">
5498+
<indexterm>
5499+
<primary>pg_stat_get_session</primary>
5500+
</indexterm>
5501+
<function>pg_stat_get_session</function> ( <type>integer</type> )
5502+
<returnvalue>setof record</returnvalue>
5503+
</para>
5504+
<para>
5505+
Returns a record of information about the backend with the specified
5506+
process ID, or one record for each active backend in the system
5507+
if <literal>NULL</literal> is specified. The fields returned are a
5508+
subset of those in the <structname>pg_stat_session</structname> view.
5509+
</para></entry>
5510+
</row>
5511+
53595512
<row>
53605513
<entry role="func_table_entry"><para role="func_signature">
53615514
<indexterm>

‎src/backend/catalog/system_views.sql‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -871,6 +871,21 @@ CREATE VIEW pg_stat_activity AS
871871
LEFT JOIN pg_database AS D ON (S.datid = D.oid)
872872
LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid);
873873

874+
CREATE VIEW pg_stat_session AS
875+
SELECT
876+
s.pid,
877+
s.total_running_time,
878+
s.total_running_count,
879+
s.total_idle_time,
880+
s.total_idle_count,
881+
s.total_transaction_idle_time,
882+
s.total_transaction_idle_count,
883+
s.total_transaction_idle_aborted_time,
884+
s.total_transaction_idle_aborted_count,
885+
s.total_fastpath_time,
886+
s.total_fastpath_count
887+
FROM pg_stat_get_session(NULL) as s;
888+
874889
CREATE VIEW pg_stat_replication AS
875890
SELECT
876891
S.pid,

‎src/backend/utils/activity/backend_status.c‎

Lines changed: 49 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -338,6 +338,8 @@ pgstat_bestart(void)
338338
lbeentry.st_xact_start_timestamp = 0;
339339
lbeentry.st_databaseid = MyDatabaseId;
340340

341+
MemSet(&lbeentry.st_session, 0, sizeof(lbeentry.st_session));
342+
341343
/* We have userid for client-backends, wal-sender and bgworker processes */
342344
if (lbeentry.st_backendType == B_BACKEND
343345
|| lbeentry.st_backendType == B_WAL_SENDER
@@ -525,6 +527,9 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
525527
TimestampTz current_timestamp;
526528
int len = 0;
527529

530+
PgBackendSessionStatus st_session_diff;
531+
MemSet(&st_session_diff, 0, sizeof(st_session_diff));
532+
528533
TRACE_POSTGRESQL_STATEMENT_STATUS(cmd_str);
529534

530535
if (!beentry)
@@ -550,6 +555,7 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
550555
beentry->st_xact_start_timestamp = 0;
551556
beentry->st_query_id = UINT64CONST(0);
552557
proc->wait_event_info = 0;
558+
MemSet(&beentry->st_session, 0, sizeof(beentry->st_session));
553559
PGSTAT_END_WRITE_ACTIVITY(beentry);
554560
}
555561
return;
@@ -572,27 +578,46 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
572578
current_timestamp = GetCurrentTimestamp();
573579

574580
/*
575-
* If the state has changed from "active" or "idle in transaction",
576-
* calculate the duration.
581+
* If the state has changed, update per-database and per-session counters.
577582
*/
578-
if ((beentry->st_state == STATE_RUNNING ||
579-
beentry->st_state == STATE_FASTPATH ||
580-
beentry->st_state == STATE_IDLEINTRANSACTION ||
581-
beentry->st_state == STATE_IDLEINTRANSACTION_ABORTED) &&
583+
if ((PGSTAT_IS_ACTIVE(beentry) ||
584+
PGSTAT_IS_IDLEINTRANSACTION(beentry) ||
585+
PGSTAT_IS_IDLEINTRANSACTION_ABORTED(beentry) ||
586+
PGSTAT_IS_IDLE(beentry)) &&
582587
state != beentry->st_state)
583588
{
584589
long secs;
585590
int usecs;
591+
int64 usecs_diff;
586592

587593
TimestampDifference(beentry->st_state_start_timestamp,
588594
current_timestamp,
589595
&secs, &usecs);
596+
usecs_diff = secs * 1000000 + usecs;
590597

591-
if (beentry->st_state == STATE_RUNNING ||
592-
beentry->st_state == STATE_FASTPATH)
598+
/* Keep statistics for pg_stat_database intact */
599+
if (PGSTAT_IS_ACTIVE(beentry))
593600
pgstat_count_conn_active_time((PgStat_Counter) secs * 1000000 + usecs);
594-
else
601+
else if (PGSTAT_IS_IDLEINTRANSACTION(beentry) ||
602+
PGSTAT_IS_IDLEINTRANSACTION_ABORTED(beentry))
595603
pgstat_count_conn_txn_idle_time((PgStat_Counter) secs * 1000000 + usecs);
604+
605+
if (PGSTAT_IS_RUNNING(beentry)) {
606+
st_session_diff.total_running_time = usecs_diff;
607+
st_session_diff.total_running_count += 1;
608+
} else if (PGSTAT_IS_IDLE(beentry)){
609+
st_session_diff.total_idle_time = usecs_diff;
610+
st_session_diff.total_idle_count += 1;
611+
} else if (PGSTAT_IS_IDLEINTRANSACTION(beentry)){
612+
st_session_diff.total_transaction_idle_time = usecs_diff;
613+
st_session_diff.total_transaction_idle_count += 1;
614+
} else if (PGSTAT_IS_IDLEINTRANSACTION_ABORTED(beentry)){
615+
st_session_diff.total_transaction_idle_aborted_time = usecs_diff;
616+
st_session_diff.total_transaction_idle_aborted_count += 1;
617+
} else if (PGSTAT_IS_FASTPATH(beentry)){
618+
st_session_diff.total_fastpath_time = usecs_diff;
619+
st_session_diff.total_fastpath_count += 1;
620+
}
596621
}
597622

598623
/*
@@ -618,6 +643,21 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
618643
beentry->st_activity_start_timestamp = start_timestamp;
619644
}
620645

646+
beentry->st_session.total_running_time += st_session_diff.total_running_time;
647+
beentry->st_session.total_running_count += st_session_diff.total_running_count;
648+
649+
beentry->st_session.total_idle_time += st_session_diff.total_idle_time;
650+
beentry->st_session.total_idle_count += st_session_diff.total_idle_count;
651+
652+
beentry->st_session.total_transaction_idle_time += st_session_diff.total_transaction_idle_time;
653+
beentry->st_session.total_transaction_idle_count += st_session_diff.total_transaction_idle_count;
654+
655+
beentry->st_session.total_transaction_idle_aborted_time += st_session_diff.total_transaction_idle_aborted_time;
656+
beentry->st_session.total_transaction_idle_aborted_count += st_session_diff.total_transaction_idle_aborted_count;
657+
658+
beentry->st_session.total_fastpath_time += st_session_diff.total_fastpath_time;
659+
beentry->st_session.total_fastpath_count += st_session_diff.total_fastpath_count;
660+
621661
PGSTAT_END_WRITE_ACTIVITY(beentry);
622662
}
623663

‎src/backend/utils/adt/pgstatfuncs.c‎

Lines changed: 70 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -296,6 +296,76 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
296296
return (Datum) 0;
297297
}
298298

299+
/*
300+
* Returns accumulated statistics of current PG backends.
301+
*/
302+
Datum
303+
pg_stat_get_session(PG_FUNCTION_ARGS)
304+
{
305+
#define PG_STAT_GET_SESSION_COLS 11
306+
int num_backends = pgstat_fetch_stat_numbackends();
307+
int curr_backend;
308+
int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0);
309+
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
310+
311+
InitMaterializedSRF(fcinfo, 0);
312+
313+
/* 1-based index */
314+
for (curr_backend = 1; curr_backend <= num_backends; curr_backend++)
315+
{
316+
/* for each row */
317+
Datum values[PG_STAT_GET_SESSION_COLS] = {0};
318+
bool nulls[PG_STAT_GET_SESSION_COLS] = {0};
319+
LocalPgBackendStatus *local_beentry;
320+
PgBackendStatus *beentry;
321+
322+
/* Get the next one in the list */
323+
local_beentry = pgstat_fetch_stat_local_beentry(curr_backend);
324+
beentry = &local_beentry->backendStatus;
325+
326+
/* If looking for specific PID, ignore all the others */
327+
if (pid != -1 && beentry->st_procpid != pid)
328+
continue;
329+
330+
/* Values available to all callers */
331+
values[0] = Int32GetDatum(beentry->st_procpid);
332+
333+
/* Values only available to role member or pg_read_all_stats */
334+
if (HAS_PGSTAT_PERMISSIONS(beentry->st_userid)){
335+
/* convert to msec */
336+
values[1] = Float8GetDatum(beentry->st_session.total_running_time / 1000.0);
337+
values[2] = Int64GetDatum(beentry->st_session.total_running_count);
338+
values[3] = Float8GetDatum(beentry->st_session.total_idle_time / 1000.0);
339+
values[4] = Int64GetDatum(beentry->st_session.total_idle_count);
340+
values[5] = Float8GetDatum(beentry->st_session.total_transaction_idle_time / 1000.0);
341+
values[6] = Int64GetDatum(beentry->st_session.total_transaction_idle_count);
342+
values[7] = Float8GetDatum(beentry->st_session.total_transaction_idle_aborted_time / 1000.0);
343+
values[8] = Int64GetDatum(beentry->st_session.total_transaction_idle_aborted_count);
344+
values[9] = Float8GetDatum(beentry->st_session.total_fastpath_time / 1000.0);
345+
values[10] = Int64GetDatum(beentry->st_session.total_fastpath_count);
346+
} else {
347+
nulls[1] = true;
348+
nulls[2] = true;
349+
nulls[3] = true;
350+
nulls[4] = true;
351+
nulls[5] = true;
352+
nulls[6] = true;
353+
nulls[7] = true;
354+
nulls[8] = true;
355+
nulls[9] = true;
356+
nulls[10] = true;
357+
}
358+
359+
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
360+
361+
/* If only a single backend was requested, and we found it, break. */
362+
if (pid != -1)
363+
break;
364+
}
365+
366+
return (Datum) 0;
367+
}
368+
299369
/*
300370
* Returns activity of PG backends.
301371
*/

‎src/include/catalog/pg_proc.dat‎

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5381,6 +5381,15 @@
53815381
proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
53825382
proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,leader_pid,query_id}',
53835383
prosrc => 'pg_stat_get_activity' },
5384+
{ oid => '2173',
5385+
descr => 'statistics: cumulative information about currently active backends',
5386+
proname => 'pg_stat_get_session', prorows => '100', proisstrict => 'f',
5387+
proretset => 't', provolatile => 's', proparallel => 'r',
5388+
prorettype => 'record', proargtypes => 'int4',
5389+
proallargtypes => '{int4,int4,float8,int8,float8,int8,float8,int8,float8,int8,float8,int8}',
5390+
proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o}',
5391+
proargnames => '{pid,pid,total_running_time,total_running_count,total_idle_time,total_idle_count,total_transaction_idle_time,total_transaction_idle_count,total_transaction_idle_aborted_time,total_transaction_idle_aborted_count,total_fastpath_time,total_fastpath_count}',
5392+
prosrc => 'pg_stat_get_session' },
53845393
{ oid => '3318',
53855394
descr => 'statistics: information about progress of backends running maintenance command',
53865395
proname => 'pg_stat_get_progress_info', prorows => '100', proretset => 't',

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