Enhance pg_stat_reset_single_table_counters function.

This commit allows pg_stat_reset_single_table_counters() to reset statistics
for a single relation shared across all databases in the cluster to zero.

Bump catalog version.

Author: B Sadhu Prasad Patro
Reviewed-by: Mahendra Singh Thalor, Himanshu Upadhyaya, Dilip Kumar, Fujii Masao
Discussion: https://postgr.es/m/CAFF0-CGy7EHeF=AqqkGMF85cySPQBgDcvNk73G2O0vL94O5U5A@mail.gmail.com

Author: MasaoFujii

doc/src/sgml/monitoring.sgml

@@ -5097,7 +5097,7 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        </para>
        <para>
         Resets statistics for a single table or index in the current database
-        to zero.
+        or shared across all databases in the cluster to zero.
        </para>
        <para>
         This function is restricted to superusers by default, but other users

src/backend/postmaster/pgstat.c

@@ -38,6 +38,7 @@
 #include "access/transam.h"
 #include "access/twophase_rmgr.h"
 #include "access/xact.h"
+#include "catalog/catalog.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_proc.h"
 #include "common/ip.h"
@@ -5140,15 +5141,19 @@ pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 /* ----------
  * pgstat_recv_resetsinglecounter() -
  *
- *	Reset a statistics for a single object
+ *	Reset a statistics for a single object, which may be of current
+ *	database or shared across all databases in the cluster.
  * ----------
  */
 static void
 pgstat_recv_resetsinglecounter(PgStat_MsgResetsinglecounter *msg, int len)
 {
 	PgStat_StatDBEntry *dbentry;
 
-	dbentry = pgstat_get_db_entry(msg->m_databaseid, false);
+	if (IsSharedRelation(msg->m_objectid))
+		dbentry = pgstat_get_db_entry(InvalidOid, false);
+	else
+		dbentry = pgstat_get_db_entry(msg->m_databaseid, false);
 
 	if (!dbentry)
 		return;

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202108311
+#define CATALOG_VERSION_NO	202109021
 
 #endif

src/include/catalog/pg_proc.dat

@@ -5754,7 +5754,7 @@
   proname => 'pg_stat_reset_shared', provolatile => 'v', prorettype => 'void',
   proargtypes => 'text', prosrc => 'pg_stat_reset_shared' },
 { oid => '3776',
-  descr => 'statistics: reset collected statistics for a single table or index in the current database',
+  descr => 'statistics: reset collected statistics for a single table or index in the current database or shared across all databases in the cluster',
   proname => 'pg_stat_reset_single_table_counters', provolatile => 'v',
   prorettype => 'void', proargtypes => 'oid',
   prosrc => 'pg_stat_reset_single_table_counters' },