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Add pg_stat_session #8

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134 changes: 134 additions & 0 deletions doc/src/sgml/monitoring.sgml
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Original file line number Diff line number Diff line change
Expand Up @@ -414,6 +414,20 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
See <xref linkend="copy-progress-reporting"/>.
</entry>
</row>

<row>
<entry>
<structname>pg_stat_session</structname>
<indexterm><primary>pg_stat_session</primary></indexterm>
</entry>
<entry>
One row per client backend, showing information related to
the currently accumulated activity of that process, such as time spent in
a certain state.
See <link linkend="monitoring-pg-stat-session-view">
<structname>pg_stat_session</structname></link> for details.
</entry>
</row>
</tbody>
</tgroup>
</table>
Expand Down Expand Up @@ -5755,6 +5769,110 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</tgroup>
</table>

<table id="monitoring-pg-stat-session-view" xreflabel="pg_stat_session">
<title><structname>pg_stat_session</structname> View</title>
<tgroup cols="1">
<thead>
<row>
<entry role="catalog_table_entry"><para role="column_definition">
Column Type
</para>
<para>
Description
</para></entry>
</row>
</thead>

<tbody>
<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>pid</structfield> <type>integer</type>
</para>
<para>
Process ID of this client backend.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_running_time</structfield> <type>double precision</type>
</para>
<para>
Time in milliseconds this backend spent in the <literal>running</literal> or <literal>fastpath</literal> state.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_running_count</structfield> <type>bigint</type>
</para>
<para>
Number of times this backend switched to the <literal>running</literal> or <literal>fastpath</literal> state.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_idle_time</structfield> <type>double precision</type>
</para>
<para>
Time in milliseconds this backend spent in the <literal>idle</literal> state.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_idle_count</structfield> <type>bigint</type>
</para>
<para>
Number of times this backend switched to the <literal>idle</literal> state.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_transaction_idle_time</structfield> <type>double precision</type>
</para>
<para>
Time in milliseconds this backend spent in the <literal>idle in transaction</literal>
state.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_transaction_idle_count</structfield> <type>bigint</type>
</para>
<para>
Number of times this backend switched to the <literal>idle in transaction</literal>
state.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_transaction_idle_aborted_time</structfield> <type>double precision</type>
</para>
<para>
Time in milliseconds this backend spent in the <literal>idle in transaction (aborted)</literal>
state.
</para></entry>
</row>

<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>total_transaction_idle_aborted_count</structfield> <type>bigint</type>
</para>
<para>
Number of times this backend switched to the <literal>idle in transaction (aborted)</literal>
state.
</para></entry>
</row>

</tbody>
</tgroup>
</table>

</sect2>

<sect2 id="monitoring-stats-functions">
Expand Down Expand Up @@ -5822,6 +5940,22 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</para></entry>
</row>

<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
<primary>pg_stat_get_session</primary>
</indexterm>
<function>pg_stat_get_session</function> ( <type>integer</type> )
<returnvalue>setof record</returnvalue>
</para>
<para>
Returns a record of information about the client backend with the specified
process ID, or one record for each active backend in the system
if <literal>NULL</literal> is specified. The fields returned are a
subset of those in the <structname>pg_stat_session</structname> view.
</para></entry>
</row>

<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
Expand Down
13 changes: 13 additions & 0 deletions src/backend/catalog/system_views.sql
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Expand Up @@ -872,6 +872,19 @@ CREATE VIEW pg_stat_activity AS
LEFT JOIN pg_database AS D ON (S.datid = D.oid)
LEFT JOIN pg_authid AS U ON (S.usesysid = U.oid);

CREATE VIEW pg_stat_session AS
SELECT
s.pid,
s.total_running_time,
s.total_running_count,
s.total_idle_time,
s.total_idle_count,
s.total_transaction_idle_time,
s.total_transaction_idle_count,
s.total_transaction_idle_aborted_time,
s.total_transaction_idle_aborted_count
FROM pg_stat_get_session(NULL) as s;

CREATE VIEW pg_stat_replication AS
SELECT
S.pid,
Expand Down
57 changes: 47 additions & 10 deletions src/backend/utils/activity/backend_status.c
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Expand Up @@ -338,6 +338,8 @@ pgstat_bestart(void)
lbeentry.st_xact_start_timestamp = 0;
lbeentry.st_databaseid = MyDatabaseId;

MemSet(&lbeentry.st_session, 0, sizeof(lbeentry.st_session));

/* We have userid for client-backends, wal-sender and bgworker processes */
if (lbeentry.st_backendType == B_BACKEND
|| lbeentry.st_backendType == B_WAL_SENDER
Expand Down Expand Up @@ -526,6 +528,9 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
TimestampTz current_timestamp;
int len = 0;

PgBackendSessionStatus st_session_diff;
MemSet(&st_session_diff, 0, sizeof(st_session_diff));

TRACE_POSTGRESQL_STATEMENT_STATUS(cmd_str);

if (!beentry)
Expand All @@ -551,6 +556,7 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
beentry->st_xact_start_timestamp = 0;
beentry->st_query_id = UINT64CONST(0);
proc->wait_event_info = 0;
MemSet(&beentry->st_session, 0, sizeof(beentry->st_session));
PGSTAT_END_WRITE_ACTIVITY(beentry);
}
return;
Expand All @@ -573,27 +579,44 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
current_timestamp = GetCurrentTimestamp();

/*
* If the state has changed from "active" or "idle in transaction",
* calculate the duration.
* If a client backend has changed state, update per-database and per-session counters.
*/
if ((beentry->st_state == STATE_RUNNING ||
beentry->st_state == STATE_FASTPATH ||
beentry->st_state == STATE_IDLEINTRANSACTION ||
beentry->st_state == STATE_IDLEINTRANSACTION_ABORTED) &&
state != beentry->st_state)
if ((PGSTAT_IS_ACTIVE(beentry) ||
PGSTAT_IS_IDLEINTRANSACTION(beentry) ||
PGSTAT_IS_IDLEINTRANSACTION_ABORTED(beentry) ||
PGSTAT_IS_IDLE(beentry)) &&
state != beentry->st_state &&
beentry->st_backendType == B_BACKEND)
{
long secs;
int usecs;
int64 usecs_diff;

TimestampDifference(beentry->st_state_start_timestamp,
current_timestamp,
&secs, &usecs);
usecs_diff = secs * 1000000 + usecs;

if (beentry->st_state == STATE_RUNNING ||
beentry->st_state == STATE_FASTPATH)
/* Keep statistics for pg_stat_database intact */
if (PGSTAT_IS_ACTIVE(beentry))
pgstat_count_conn_active_time((PgStat_Counter) secs * 1000000 + usecs);
else
else if (PGSTAT_IS_IDLEINTRANSACTION(beentry) ||
PGSTAT_IS_IDLEINTRANSACTION_ABORTED(beentry))
pgstat_count_conn_txn_idle_time((PgStat_Counter) secs * 1000000 + usecs);

if (PGSTAT_IS_ACTIVE(beentry)) {
st_session_diff.total_running_time = usecs_diff;
st_session_diff.total_running_count += 1;
} else if (PGSTAT_IS_IDLE(beentry)){
st_session_diff.total_idle_time = usecs_diff;
st_session_diff.total_idle_count += 1;
} else if (PGSTAT_IS_IDLEINTRANSACTION(beentry)){
st_session_diff.total_transaction_idle_time = usecs_diff;
st_session_diff.total_transaction_idle_count += 1;
} else if (PGSTAT_IS_IDLEINTRANSACTION_ABORTED(beentry)){
st_session_diff.total_transaction_idle_aborted_time = usecs_diff;
st_session_diff.total_transaction_idle_aborted_count += 1;
}
}

/*
Expand All @@ -619,6 +642,20 @@ pgstat_report_activity(BackendState state, const char *cmd_str)
beentry->st_activity_start_timestamp = start_timestamp;
}

if (beentry->st_backendType == B_BACKEND) {
beentry->st_session.total_running_time += st_session_diff.total_running_time;
beentry->st_session.total_running_count += st_session_diff.total_running_count;

beentry->st_session.total_idle_time += st_session_diff.total_idle_time;
beentry->st_session.total_idle_count += st_session_diff.total_idle_count;

beentry->st_session.total_transaction_idle_time += st_session_diff.total_transaction_idle_time;
beentry->st_session.total_transaction_idle_count += st_session_diff.total_transaction_idle_count;

beentry->st_session.total_transaction_idle_aborted_time += st_session_diff.total_transaction_idle_aborted_time;
beentry->st_session.total_transaction_idle_aborted_count += st_session_diff.total_transaction_idle_aborted_count;
}

PGSTAT_END_WRITE_ACTIVITY(beentry);
}

Expand Down
70 changes: 70 additions & 0 deletions src/backend/utils/adt/pgstatfuncs.c
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Expand Up @@ -297,6 +297,76 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
return (Datum) 0;
}

/*
* Returns accumulated statistics of current PG backends.
*/
Datum
pg_stat_get_session(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_SESSION_COLS 9
int num_backends = pgstat_fetch_stat_numbackends();
int curr_backend;
int pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0);
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;

InitMaterializedSRF(fcinfo, 0);

/* 1-based index */
for (curr_backend = 1; curr_backend <= num_backends; curr_backend++)
{
/* for each row */
Datum values[PG_STAT_GET_SESSION_COLS] = {0};
bool nulls[PG_STAT_GET_SESSION_COLS] = {0};
LocalPgBackendStatus *local_beentry;
PgBackendStatus *beentry;

/* Get the next one in the list */
local_beentry = pgstat_fetch_stat_local_beentry(curr_backend);
beentry = &local_beentry->backendStatus;

/* Report statistics only for client backends */
if (beentry->st_backendType != B_BACKEND)
continue;

/* If looking for specific PID, ignore all the others */
if (pid != -1 && beentry->st_procpid != pid)
continue;

/* Values available to all callers */
values[0] = Int32GetDatum(beentry->st_procpid);

/* Values only available to role member or pg_read_all_stats */
if (HAS_PGSTAT_PERMISSIONS(beentry->st_userid)){
/* convert to msec */
values[1] = Float8GetDatum(beentry->st_session.total_running_time / 1000.0);
values[2] = Int64GetDatum(beentry->st_session.total_running_count);
values[3] = Float8GetDatum(beentry->st_session.total_idle_time / 1000.0);
values[4] = Int64GetDatum(beentry->st_session.total_idle_count);
values[5] = Float8GetDatum(beentry->st_session.total_transaction_idle_time / 1000.0);
values[6] = Int64GetDatum(beentry->st_session.total_transaction_idle_count);
values[7] = Float8GetDatum(beentry->st_session.total_transaction_idle_aborted_time / 1000.0);
values[8] = Int64GetDatum(beentry->st_session.total_transaction_idle_aborted_count);
} else {
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
}

tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);

/* If only a single backend was requested, and we found it, break. */
if (pid != -1)
break;
}

return (Datum) 0;
}

/*
* Returns activity of PG backends.
*/
Expand Down
9 changes: 9 additions & 0 deletions src/include/catalog/pg_proc.dat
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Expand Up @@ -5417,6 +5417,15 @@
proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}',
prosrc => 'pg_stat_get_activity' },
{ oid => '2173',
descr => 'statistics: cumulative information about currently active client backends',
proname => 'pg_stat_get_session', prorows => '100', proisstrict => 'f',
proretset => 't', provolatile => 's', proparallel => 'r',
prorettype => 'record', proargtypes => 'int4',
proallargtypes => '{int4,int4,float8,int8,float8,int8,float8,int8,float8,int8}',
proargmodes => '{i,o,o,o,o,o,o,o,o,o}',
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}',
prosrc => 'pg_stat_get_session' },
{ oid => '3318',
descr => 'statistics: information about progress of backends running maintenance command',
proname => 'pg_stat_get_progress_info', prorows => '100', proretset => 't',
Expand Down
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