Take the statistics collector out of the loop for monitoring backends'

current commands; instead, store current-status information in shared
memory.  This substantially reduces the overhead of stats_command_string
and also ensures that pg_stat_activity is fully up to date at all times.
Per my recent proposal.

src/backend/postmaster/postmaster.c

@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.486 2006/06/18 15:38:37 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.487 2006/06/19 01:51:21 tgl Exp $
  *
  * NOTES
  *
@@ -2109,9 +2109,6 @@ reaper(SIGNAL_ARGS)
 		{
 			AutoVacPID = 0;
 			autovac_stopped();
-			/* Tell the collector about process termination */
-			pgstat_beterm(pid);
-
 			if (exitstatus != 0)
 				HandleChildCrash(pid, exitstatus,
 								 _("autovacuum process"));
@@ -2252,8 +2249,6 @@ CleanupBackend(int pid,
 #ifdef EXEC_BACKEND
 			ShmemBackendArrayRemove(pid);
 #endif
-			/* Tell the collector about backend termination */
-			pgstat_beterm(pid);
 			break;
 		}
 	}
@@ -2299,8 +2294,6 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 #ifdef EXEC_BACKEND
 			ShmemBackendArrayRemove(pid);
 #endif
-			/* Tell the collector about backend termination */
-			pgstat_beterm(pid);
 			/* Keep looping so we can signal remaining backends */
 		}
 		else

src/backend/storage/ipc/ipci.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/ipc/ipci.c,v 1.83 2006/05/08 00:00:10 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/ipc/ipci.c,v 1.84 2006/06/19 01:51:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -21,6 +21,7 @@
 #include "access/twophase.h"
 #include "access/xlog.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgwriter.h"
 #include "postmaster/postmaster.h"
 #include "storage/bufmgr.h"
@@ -86,6 +87,7 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
 		size = add_size(size, MultiXactShmemSize());
 		size = add_size(size, LWLockShmemSize());
 		size = add_size(size, ProcArrayShmemSize());
+		size = add_size(size, BackendStatusShmemSize());
 		size = add_size(size, SInvalShmemSize());
 		size = add_size(size, FreeSpaceShmemSize());
 		size = add_size(size, BgWriterShmemSize());
@@ -167,6 +169,7 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
 	if (!IsUnderPostmaster)
 		InitProcGlobal();
 	CreateSharedProcArray();
+	CreateSharedBackendStatus();
 
 	/*
 	 * Set up shared-inval messaging

src/backend/storage/ipc/procarray.c

@@ -23,7 +23,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.11 2006/03/05 15:58:37 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.12 2006/06/19 01:51:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -732,42 +732,6 @@ IsBackendPid(int pid)
 	return (BackendPidGetProc(pid) != NULL);
 }
 
-/*
- * GetAllBackendPids -- get an array of all current backends' PIDs
- *
- * The result is a palloc'd array with the number of active backends in
- * entry [0], their PIDs in entries [1] .. [n].  The caller must bear in
- * mind that the result may already be obsolete when returned.
- */
-int *
-GetAllBackendPids(void)
-{
-	int		   *result;
-	int			npids;
-	ProcArrayStruct *arrayP = procArray;
-	int			index;
-
-	result = (int *) palloc((MaxBackends + 1) * sizeof(int));
-	npids = 0;
-
-	LWLockAcquire(ProcArrayLock, LW_SHARED);
-
-	for (index = 0; index < arrayP->numProcs; index++)
-	{
-		PGPROC	   *proc = arrayP->procs[index];
-
-		if (proc->pid != 0)		/* ignore dummy procs */
-			result[++npids] = proc->pid;
-	}
-
-	LWLockRelease(ProcArrayLock);
-
-	Assert(npids <= MaxBackends);
-
-	result[0] = npids;
-	return result;
-}
-
 /*
  * CountActiveBackends --- count backends (other than myself) that are in
  *		active transactions.  This is used as a heuristic to decide if

src/backend/utils/adt/pgstatfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/pgstatfuncs.c,v 1.29 2006/05/19 19:08:26 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/pgstatfuncs.c,v 1.30 2006/06/19 01:51:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -61,11 +61,9 @@ extern Datum pg_stat_get_db_blocks_hit(PG_FUNCTION_ARGS);
 Datum
 pg_stat_get_numscans(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -79,11 +77,9 @@ pg_stat_get_numscans(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_tuples_returned(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -97,11 +93,9 @@ pg_stat_get_tuples_returned(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_tuples_fetched(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -115,11 +109,9 @@ pg_stat_get_tuples_fetched(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_tuples_inserted(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -133,11 +125,9 @@ pg_stat_get_tuples_inserted(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_tuples_updated(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -151,11 +141,9 @@ pg_stat_get_tuples_updated(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_tuples_deleted(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -169,11 +157,9 @@ pg_stat_get_tuples_deleted(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_blocks_fetched(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -187,11 +173,9 @@ pg_stat_get_blocks_fetched(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_blocks_hit(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	int64		result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -204,11 +188,9 @@ pg_stat_get_blocks_hit(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_last_vacuum_time(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	TimestampTz	result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -224,11 +206,9 @@ pg_stat_get_last_vacuum_time(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_last_autovacuum_time(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	TimestampTz	result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -244,11 +224,9 @@ pg_stat_get_last_autovacuum_time(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_last_analyze_time(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	TimestampTz	result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -264,11 +242,9 @@ pg_stat_get_last_analyze_time(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_last_autoanalyze_time(PG_FUNCTION_ARGS)
 {
-	PgStat_StatTabEntry *tabentry;
-	Oid			relid;
+	Oid			relid = PG_GETARG_OID(0);
 	TimestampTz	result;
-
-	relid = PG_GETARG_OID(0);
+	PgStat_StatTabEntry *tabentry;
 
 	if ((tabentry = pgstat_fetch_stat_tabentry(relid)) == NULL)
 		result = 0;
@@ -342,75 +318,59 @@ pg_stat_reset(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_backend_pid(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
-	int32		beid;
-
-	beid = PG_GETARG_INT32(0);
+	int32		beid = PG_GETARG_INT32(0);
+	PgBackendStatus *beentry;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
 
-	PG_RETURN_INT32(beentry->procpid);
+	PG_RETURN_INT32(beentry->st_procpid);
 }
 
 
 Datum
 pg_stat_get_backend_dbid(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
-	int32		beid;
-
-	beid = PG_GETARG_INT32(0);
+	int32		beid = PG_GETARG_INT32(0);
+	PgBackendStatus *beentry;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
 
-	/* Not initialized yet? */
-	if (!OidIsValid(beentry->databaseid))
-		PG_RETURN_NULL();
-
-	PG_RETURN_OID(beentry->databaseid);
+	PG_RETURN_OID(beentry->st_databaseid);
 }
 
 
 Datum
 pg_stat_get_backend_userid(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
-	int32		beid;
-
-	beid = PG_GETARG_INT32(0);
+	int32		beid = PG_GETARG_INT32(0);
+	PgBackendStatus *beentry;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
 
-	/* Not initialized yet? */
-	if (!OidIsValid(beentry->userid))
-		PG_RETURN_NULL();
-
-	PG_RETURN_OID(beentry->userid);
+	PG_RETURN_OID(beentry->st_userid);
 }
 
 
 Datum
 pg_stat_get_backend_activity(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
-	int32		beid;
-	int			len;
-	char	   *activity;
+	int32		beid = PG_GETARG_INT32(0);
 	text	   *result;
-
-	beid = PG_GETARG_INT32(0);
+	PgBackendStatus *beentry;
+	int			len;
+	const char *activity;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		activity = "<backend information not available>";
-	else if (!superuser() && beentry->userid != GetUserId())
+	else if (!superuser() && beentry->st_userid != GetUserId())
 		activity = "<insufficient privilege>";
-	else if (*(beentry->activity) == '\0')
+	else if (*(beentry->st_activity) == '\0')
 		activity = "<command string not enabled>";
 	else
-		activity = beentry->activity;
+		activity = beentry->st_activity;
 
 	len = strlen(activity);
 	result = palloc(VARHDRSZ + len);
@@ -426,15 +386,15 @@ pg_stat_get_backend_activity_start(PG_FUNCTION_ARGS)
 {
 	int32		beid = PG_GETARG_INT32(0);
 	TimestampTz result;
-	PgStat_StatBeEntry *beentry;
+	PgBackendStatus *beentry;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
 
-	if (!superuser() && beentry->userid != GetUserId())
+	if (!superuser() && beentry->st_userid != GetUserId())
 		PG_RETURN_NULL();
 
-	result = beentry->activity_start_timestamp;
+	result = beentry->st_activity_start_timestamp;
 
 	/*
 	 * No time recorded for start of current query -- this is the case if the
@@ -451,15 +411,15 @@ pg_stat_get_backend_start(PG_FUNCTION_ARGS)
 {
 	int32		beid = PG_GETARG_INT32(0);
 	TimestampTz result;
-	PgStat_StatBeEntry *beentry;
+	PgBackendStatus *beentry;
 
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
 
-	if (!superuser() && beentry->userid != GetUserId())
+	if (!superuser() && beentry->st_userid != GetUserId())
 		PG_RETURN_NULL();
 
-	result = beentry->start_timestamp;
+	result = beentry->st_proc_start_timestamp;
 
 	if (result == 0)			/* probably can't happen? */
 		PG_RETURN_NULL();
@@ -471,31 +431,25 @@ pg_stat_get_backend_start(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
+	int32		beid = PG_GETARG_INT32(0);
+	PgBackendStatus *beentry;
 	SockAddr	zero_clientaddr;
-	int32		beid;
 	char		remote_host[NI_MAXHOST];
 	int			ret;
 
-	beid = PG_GETARG_INT32(0);
-
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
 
-	/* Not initialized yet? */
-	if (!OidIsValid(beentry->userid))
-		PG_RETURN_NULL();
-
-	if (!superuser() && beentry->userid != GetUserId())
+	if (!superuser() && beentry->st_userid != GetUserId())
 		PG_RETURN_NULL();
 
 	/* A zeroed client addr means we don't know */
 	memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
-	if (memcmp(&(beentry->clientaddr), &zero_clientaddr,
+	if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
 			   sizeof(zero_clientaddr) == 0))
 		PG_RETURN_NULL();
 
-	switch (beentry->clientaddr.addr.ss_family)
+	switch (beentry->st_clientaddr.addr.ss_family)
 	{
 		case AF_INET:
 #ifdef HAVE_IPV6
@@ -507,7 +461,8 @@ pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
 	}
 
 	remote_host[0] = '\0';
-	ret = pg_getnameinfo_all(&beentry->clientaddr.addr, beentry->clientaddr.salen,
+	ret = pg_getnameinfo_all(&beentry->st_clientaddr.addr,
+							 beentry->st_clientaddr.salen,
 							 remote_host, sizeof(remote_host),
 							 NULL, 0,
 							 NI_NUMERICHOST | NI_NUMERICSERV);
@@ -521,31 +476,25 @@ pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
 {
-	PgStat_StatBeEntry *beentry;
+	int32		beid = PG_GETARG_INT32(0);
+	PgBackendStatus *beentry;
 	SockAddr	zero_clientaddr;
-	int32		beid;
 	char		remote_port[NI_MAXSERV];
 	int			ret;
 
-	beid = PG_GETARG_INT32(0);
-
 	if ((beentry = pgstat_fetch_stat_beentry(beid)) == NULL)
 		PG_RETURN_NULL();
 
-	/* Not initialized yet? */
-	if (!OidIsValid(beentry->userid))
-		PG_RETURN_NULL();
-
-	if (!superuser() && beentry->userid != GetUserId())
+	if (!superuser() && beentry->st_userid != GetUserId())
 		PG_RETURN_NULL();
 
 	/* A zeroed client addr means we don't know */
 	memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
-	if (memcmp(&(beentry->clientaddr), &zero_clientaddr,
+	if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
 			   sizeof(zero_clientaddr) == 0))
 		PG_RETURN_NULL();
 
-	switch (beentry->clientaddr.addr.ss_family)
+	switch (beentry->st_clientaddr.addr.ss_family)
 	{
 		case AF_INET:
 #ifdef HAVE_IPV6
@@ -559,31 +508,35 @@ pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
 	}
 
 	remote_port[0] = '\0';
-	ret = pg_getnameinfo_all(&beentry->clientaddr.addr,
-							 beentry->clientaddr.salen,
+	ret = pg_getnameinfo_all(&beentry->st_clientaddr.addr,
+							 beentry->st_clientaddr.salen,
 							 NULL, 0,
 							 remote_port, sizeof(remote_port),
 							 NI_NUMERICHOST | NI_NUMERICSERV);
 	if (ret)
 		PG_RETURN_NULL();
 
-	PG_RETURN_DATUM(DirectFunctionCall1(int4in, CStringGetDatum(remote_port)));
+	PG_RETURN_DATUM(DirectFunctionCall1(int4in,
+										CStringGetDatum(remote_port)));
 }
 
 
 Datum
 pg_stat_get_db_numbackends(PG_FUNCTION_ARGS)
 {
-	PgStat_StatDBEntry *dbentry;
-	Oid			dbid;
+	Oid			dbid = PG_GETARG_OID(0);
 	int32		result;
+	int			tot_backends = pgstat_fetch_stat_numbackends();
+	int			beid;
 
-	dbid = PG_GETARG_OID(0);
+	result = 0;
+	for (beid = 1; beid <= tot_backends; beid++)
+	{
+		PgBackendStatus *beentry = pgstat_fetch_stat_beentry(beid);
 
-	if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
-		result = 0;
-	else
-		result = (int32) (dbentry->n_backends);
+		if (beentry && beentry->st_databaseid == dbid)
+			result++;
+	}
 
 	PG_RETURN_INT32(result);
 }
@@ -592,11 +545,9 @@ pg_stat_get_db_numbackends(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_db_xact_commit(PG_FUNCTION_ARGS)
 {
-	PgStat_StatDBEntry *dbentry;
-	Oid			dbid;
+	Oid			dbid = PG_GETARG_OID(0);
 	int64		result;
-
-	dbid = PG_GETARG_OID(0);
+	PgStat_StatDBEntry *dbentry;
 
 	if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
 		result = 0;
@@ -610,11 +561,9 @@ pg_stat_get_db_xact_commit(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_db_xact_rollback(PG_FUNCTION_ARGS)
 {
-	PgStat_StatDBEntry *dbentry;
-	Oid			dbid;
+	Oid			dbid = PG_GETARG_OID(0);
 	int64		result;
-
-	dbid = PG_GETARG_OID(0);
+	PgStat_StatDBEntry *dbentry;
 
 	if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
 		result = 0;
@@ -628,11 +577,9 @@ pg_stat_get_db_xact_rollback(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_db_blocks_fetched(PG_FUNCTION_ARGS)
 {
-	PgStat_StatDBEntry *dbentry;
-	Oid			dbid;
+	Oid			dbid = PG_GETARG_OID(0);
 	int64		result;
-
-	dbid = PG_GETARG_OID(0);
+	PgStat_StatDBEntry *dbentry;
 
 	if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
 		result = 0;
@@ -646,11 +593,9 @@ pg_stat_get_db_blocks_fetched(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_db_blocks_hit(PG_FUNCTION_ARGS)
 {
-	PgStat_StatDBEntry *dbentry;
-	Oid			dbid;
+	Oid			dbid = PG_GETARG_OID(0);
 	int64		result;
-
-	dbid = PG_GETARG_OID(0);
+	PgStat_StatDBEntry *dbentry;
 
 	if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
 		result = 0;

src/backend/utils/misc/guc.c

@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.321 2006/06/05 02:49:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.322 2006/06/19 01:51:21 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -700,16 +700,6 @@ static struct config_bool ConfigureNamesBool[] =
 		&pgstat_collect_resetonpmstart,
 		false, NULL, NULL
 	},
-	{
-		{"stats_command_string", PGC_SUSET, STATS_COLLECTOR,
-			gettext_noop("Collects statistics about executing commands."),
-			gettext_noop("Enables the collection of statistics on the currently "
-					"executing command of each session, along with the time "
-						 "at which that command began execution.")
-		},
-		&pgstat_collect_querystring,
-		false, NULL, NULL
-	},
 	{
 		{"stats_row_level", PGC_SUSET, STATS_COLLECTOR,
 			gettext_noop("Collects row-level statistics on database activity."),
@@ -727,6 +717,17 @@ static struct config_bool ConfigureNamesBool[] =
 		false, NULL, NULL
 	},
 
+	{
+		{"stats_command_string", PGC_SUSET, STATS_COLLECTOR,
+			gettext_noop("Collects information about executing commands."),
+			gettext_noop("Enables the collection of information on the currently "
+					"executing command of each session, along with the time "
+						 "at which that command began execution.")
+		},
+		&pgstat_collect_querystring,
+		false, NULL, NULL
+	},
+
 	{
 		{"autovacuum", PGC_SIGHUP, AUTOVACUUM,
 			gettext_noop("Starts the autovacuum subprocess."),

src/backend/utils/misc/postgresql.conf.sample

@@ -320,6 +320,14 @@
 # RUNTIME STATISTICS
 #---------------------------------------------------------------------------
 
+# - Query/Index Statistics Collector -
+
+#stats_command_string = off
+#stats_start_collector = on		# needed for block or row stats
+#stats_block_level = off
+#stats_row_level = off
+#stats_reset_on_server_start = off
+
 # - Statistics Monitoring -
 
 #log_parser_stats = off
@@ -327,14 +335,6 @@
 #log_executor_stats = off
 #log_statement_stats = off
 
-# - Query/Index Statistics Collector -
-
-#stats_start_collector = on
-#stats_command_string = off
-#stats_block_level = off
-#stats_row_level = off
-#stats_reset_on_server_start = off
-
 
 #---------------------------------------------------------------------------
 # AUTOVACUUM PARAMETERS