Extend PgStat_HashKey.objid from 4 to 8 bytes

This opens the possibility to define keys for more types of statistics
kinds in PgStat_HashKey, the first case being 8-byte query IDs for
statistics like pg_stat_statements.

This increases the size of PgStat_HashKey from 12 to 16 bytes, while
PgStatShared_HashEntry, entry stored in the dshash for pgstats, keeps
the same size due to alignment.

xl_xact_stats_item, that tracks the stats items to drop in commit WAL
records, is increased from 12 to 16 bytes.  Note that individual chunks
in commit WAL records should be multiples of sizeof(int), hence 8-byte
object IDs are stored as two uint32, based on a suggestion from Heikki
Linnakangas.

While on it, the field of PgStat_HashKey is renamed from "objoid" to
"objid", as for some stats kinds this field does not refer to OIDs but
just IDs, like for replication slot stats.

This commit bumps the following format variables:
- PGSTAT_FILE_FORMAT_ID, as PgStat_HashKey is written to the stats file
for non-serialized stats kinds in the dshash table.
- XLOG_PAGE_MAGIC for the changes in xl_xact_stats_item.
- Catalog version, for the SQL function pg_stat_have_stats().

Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/ZsvTS9EW79Up8I62@paquier.xyz

7 files changed, 65 insertions, 52 deletions

diff --git a/src/backend/access/rmgrdesc/xactdesc.c b/src/backend/access/rmgrdesc/xactdesc.c
index dccca201e05..889cb955c18 100644
--- a/src/backend/access/rmgrdesc/xactdesc.c
+++ b/src/backend/access/rmgrdesc/xactdesc.c
@@ -319,10 +319,13 @@ xact_desc_stats(StringInfo buf, const char *label,
 		appendStringInfo(buf, "; %sdropped stats:", label);
 		for (i = 0; i < ndropped; i++)
 		{
-			appendStringInfo(buf, " %d/%u/%u",
+			uint64		objid =
+				((uint64) dropped_stats[i].objid_hi) << 32 | dropped_stats[i].objid_lo;
+
+			appendStringInfo(buf, " %d/%u/%llu",
 							 dropped_stats[i].kind,
 							 dropped_stats[i].dboid,
-							 dropped_stats[i].objoid);
+							 (unsigned long long) objid);
 		}
 	}
 }
diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 623b9539b15..b0d0de051e7 100644
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -684,7 +684,7 @@ REVOKE EXECUTE ON FUNCTION pg_stat_reset_single_function_counters(oid) FROM publ
 
 REVOKE EXECUTE ON FUNCTION pg_stat_reset_replication_slot(text) FROM public;
 
-REVOKE EXECUTE ON FUNCTION pg_stat_have_stats(text, oid, oid) FROM public;
+REVOKE EXECUTE ON FUNCTION pg_stat_have_stats(text, oid, int8) FROM public;
 
 REVOKE EXECUTE ON FUNCTION pg_stat_reset_subscription_stats(oid) FROM public;
 
diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c
index a7f2dfc744c..d1768a89f6e 100644
--- a/src/backend/utils/activity/pgstat.c
+++ b/src/backend/utils/activity/pgstat.c
@@ -846,7 +846,7 @@ pgstat_reset_counters(void)
  * GRANT system.
  */
 void
-pgstat_reset(PgStat_Kind kind, Oid dboid, Oid objoid)
+pgstat_reset(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
 	const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind);
 	TimestampTz ts = GetCurrentTimestamp();
@@ -855,7 +855,7 @@ pgstat_reset(PgStat_Kind kind, Oid dboid, Oid objoid)
 	Assert(!pgstat_get_kind_info(kind)->fixed_amount);
 
 	/* reset the "single counter" */
-	pgstat_reset_entry(kind, dboid, objoid, ts);
+	pgstat_reset_entry(kind, dboid, objid, ts);
 
 	if (!kind_info->accessed_across_databases)
 		pgstat_reset_database_timestamp(dboid, ts);
@@ -926,7 +926,7 @@ pgstat_clear_snapshot(void)
 }
 
 void *
-pgstat_fetch_entry(PgStat_Kind kind, Oid dboid, Oid objoid)
+pgstat_fetch_entry(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
 	PgStat_HashKey key;
 	PgStat_EntryRef *entry_ref;
@@ -941,7 +941,7 @@ pgstat_fetch_entry(PgStat_Kind kind, Oid dboid, Oid objoid)
 
 	key.kind = kind;
 	key.dboid = dboid;
-	key.objoid = objoid;
+	key.objid = objid;
 
 	/* if we need to build a full snapshot, do so */
 	if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_SNAPSHOT)
@@ -967,7 +967,7 @@ pgstat_fetch_entry(PgStat_Kind kind, Oid dboid, Oid objoid)
 
 	pgStatLocal.snapshot.mode = pgstat_fetch_consistency;
 
-	entry_ref = pgstat_get_entry_ref(kind, dboid, objoid, false, NULL);
+	entry_ref = pgstat_get_entry_ref(kind, dboid, objid, false, NULL);
 
 	if (entry_ref == NULL || entry_ref->shared_entry->dropped)
 	{
@@ -1036,13 +1036,13 @@ pgstat_get_stat_snapshot_timestamp(bool *have_snapshot)
 }
 
 bool
-pgstat_have_entry(PgStat_Kind kind, Oid dboid, Oid objoid)
+pgstat_have_entry(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
 	/* fixed-numbered stats always exist */
 	if (pgstat_get_kind_info(kind)->fixed_amount)
 		return true;
 
-	return pgstat_get_entry_ref(kind, dboid, objoid, false, NULL) != NULL;
+	return pgstat_get_entry_ref(kind, dboid, objid, false, NULL) != NULL;
 }
 
 /*
@@ -1257,7 +1257,7 @@ pgstat_build_snapshot_fixed(PgStat_Kind kind)
  * created, false otherwise.
  */
 PgStat_EntryRef *
-pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid, Oid objoid, bool *created_entry)
+pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid, uint64 objid, bool *created_entry)
 {
 	PgStat_EntryRef *entry_ref;
 
@@ -1272,7 +1272,7 @@ pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid, Oid objoid, bool *created
 								  ALLOCSET_SMALL_SIZES);
 	}
 
-	entry_ref = pgstat_get_entry_ref(kind, dboid, objoid,
+	entry_ref = pgstat_get_entry_ref(kind, dboid, objid,
 									 true, created_entry);
 
 	if (entry_ref->pending == NULL)
@@ -1295,11 +1295,11 @@ pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid, Oid objoid, bool *created
  * that it shouldn't be needed.
  */
 PgStat_EntryRef *
-pgstat_fetch_pending_entry(PgStat_Kind kind, Oid dboid, Oid objoid)
+pgstat_fetch_pending_entry(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
 	PgStat_EntryRef *entry_ref;
 
-	entry_ref = pgstat_get_entry_ref(kind, dboid, objoid, false, NULL);
+	entry_ref = pgstat_get_entry_ref(kind, dboid, objid, false, NULL);
 
 	if (entry_ref == NULL || entry_ref->pending == NULL)
 		return NULL;
@@ -1648,8 +1648,9 @@ pgstat_write_statsfile(XLogRecPtr redo)
 		 */
 		if (!pgstat_is_kind_valid(ps->key.kind))
 		{
-			elog(WARNING, "found unknown stats entry %u/%u/%u",
-				 ps->key.kind, ps->key.dboid, ps->key.objoid);
+			elog(WARNING, "found unknown stats entry %u/%u/%llu",
+				 ps->key.kind, ps->key.dboid,
+				 (unsigned long long) ps->key.objid);
 			continue;
 		}
 
@@ -1885,8 +1886,9 @@ pgstat_read_statsfile(XLogRecPtr redo)
 
 						if (!pgstat_is_kind_valid(key.kind))
 						{
-							elog(WARNING, "invalid stats kind for entry %u/%u/%u of type %c",
-								 key.kind, key.dboid, key.objoid, t);
+							elog(WARNING, "invalid stats kind for entry %u/%u/%llu of type %c",
+								 key.kind, key.dboid,
+								 (unsigned long long) key.objid, t);
 							goto error;
 						}
 					}
@@ -1957,8 +1959,9 @@ pgstat_read_statsfile(XLogRecPtr redo)
 					if (found)
 					{
 						dshash_release_lock(pgStatLocal.shared_hash, p);
-						elog(WARNING, "found duplicate stats entry %u/%u/%u of type %c",
-							 key.kind, key.dboid, key.objoid, t);
+						elog(WARNING, "found duplicate stats entry %u/%u/%llu of type %c",
+							 key.kind, key.dboid,
+							 (unsigned long long) key.objid, t);
 						goto error;
 					}
 
@@ -1969,8 +1972,9 @@ pgstat_read_statsfile(XLogRecPtr redo)
 									pgstat_get_entry_data(key.kind, header),
 									pgstat_get_entry_len(key.kind)))
 					{
-						elog(WARNING, "could not read data for entry %u/%u/%u of type %c",
-							 key.kind, key.dboid, key.objoid, t);
+						elog(WARNING, "could not read data for entry %u/%u/%llu of type %c",
+							 key.kind, key.dboid,
+							 (unsigned long long) key.objid, t);
 						goto error;
 					}
 
diff --git a/src/backend/utils/activity/pgstat_replslot.c b/src/backend/utils/activity/pgstat_replslot.c
index da11b867445..ddf2ab9928d 100644
--- a/src/backend/utils/activity/pgstat_replslot.c
+++ b/src/backend/utils/activity/pgstat_replslot.c
@@ -193,9 +193,9 @@ pgstat_replslot_to_serialized_name_cb(const PgStat_HashKey *key, const PgStatSha
 	 * isn't allowed to change at this point, we can assume that a slot exists
 	 * at the offset.
 	 */
-	if (!ReplicationSlotName(key->objoid, name))
-		elog(ERROR, "could not find name for replication slot index %u",
-			 key->objoid);
+	if (!ReplicationSlotName(key->objid, name))
+		elog(ERROR, "could not find name for replication slot index %llu",
+			 (unsigned long long) key->objid);
 }
 
 bool
@@ -209,7 +209,7 @@ pgstat_replslot_from_serialized_name_cb(const NameData *name, PgStat_HashKey *ke
 
 	key->kind = PGSTAT_KIND_REPLSLOT;
 	key->dboid = InvalidOid;
-	key->objoid = idx;
+	key->objid = idx;
 
 	return true;
 }
diff --git a/src/backend/utils/activity/pgstat_shmem.c b/src/backend/utils/activity/pgstat_shmem.c
index ec93bf6902f..a09c6fee055 100644
--- a/src/backend/utils/activity/pgstat_shmem.c
+++ b/src/backend/utils/activity/pgstat_shmem.c
@@ -429,10 +429,10 @@ pgstat_get_entry_ref_cached(PgStat_HashKey key, PgStat_EntryRef **entry_ref_p)
  * if the entry is newly created, false otherwise.
  */
 PgStat_EntryRef *
-pgstat_get_entry_ref(PgStat_Kind kind, Oid dboid, Oid objoid, bool create,
+pgstat_get_entry_ref(PgStat_Kind kind, Oid dboid, uint64 objid, bool create,
 					 bool *created_entry)
 {
-	PgStat_HashKey key = {.kind = kind,.dboid = dboid,.objoid = objoid};
+	PgStat_HashKey key = {.kind = kind,.dboid = dboid,.objid = objid};
 	PgStatShared_HashEntry *shhashent;
 	PgStatShared_Common *shheader = NULL;
 	PgStat_EntryRef *entry_ref;
@@ -644,13 +644,13 @@ pgstat_unlock_entry(PgStat_EntryRef *entry_ref)
  * Helper function to fetch and lock shared stats.
  */
 PgStat_EntryRef *
-pgstat_get_entry_ref_locked(PgStat_Kind kind, Oid dboid, Oid objoid,
+pgstat_get_entry_ref_locked(PgStat_Kind kind, Oid dboid, uint64 objid,
 							bool nowait)
 {
 	PgStat_EntryRef *entry_ref;
 
 	/* find shared table stats entry corresponding to the local entry */
-	entry_ref = pgstat_get_entry_ref(kind, dboid, objoid, true, NULL);
+	entry_ref = pgstat_get_entry_ref(kind, dboid, objid, true, NULL);
 
 	/* lock the shared entry to protect the content, skip if failed */
 	if (!pgstat_lock_entry(entry_ref, nowait))
@@ -820,9 +820,10 @@ pgstat_drop_entry_internal(PgStatShared_HashEntry *shent,
 	 */
 	if (shent->dropped)
 		elog(ERROR,
-			 "trying to drop stats entry already dropped: kind=%s dboid=%u objoid=%u refcount=%u",
+			 "trying to drop stats entry already dropped: kind=%s dboid=%u objid=%llu refcount=%u",
 			 pgstat_get_kind_info(shent->key.kind)->name,
-			 shent->key.dboid, shent->key.objoid,
+			 shent->key.dboid,
+			 (unsigned long long) shent->key.objid,
 			 pg_atomic_read_u32(&shent->refcount));
 	shent->dropped = true;
 
@@ -905,9 +906,9 @@ pgstat_drop_database_and_contents(Oid dboid)
  * pgstat_gc_entry_refs().
  */
 bool
-pgstat_drop_entry(PgStat_Kind kind, Oid dboid, Oid objoid)
+pgstat_drop_entry(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
-	PgStat_HashKey key = {.kind = kind,.dboid = dboid,.objoid = objoid};
+	PgStat_HashKey key = {.kind = kind,.dboid = dboid,.objid = objid};
 	PgStatShared_HashEntry *shent;
 	bool		freed = true;
 
@@ -980,13 +981,13 @@ shared_stat_reset_contents(PgStat_Kind kind, PgStatShared_Common *header,
  * Reset one variable-numbered stats entry.
  */
 void
-pgstat_reset_entry(PgStat_Kind kind, Oid dboid, Oid objoid, TimestampTz ts)
+pgstat_reset_entry(PgStat_Kind kind, Oid dboid, uint64 objid, TimestampTz ts)
 {
 	PgStat_EntryRef *entry_ref;
 
 	Assert(!pgstat_get_kind_info(kind)->fixed_amount);
 
-	entry_ref = pgstat_get_entry_ref(kind, dboid, objoid, false, NULL);
+	entry_ref = pgstat_get_entry_ref(kind, dboid, objid, false, NULL);
 	if (!entry_ref || entry_ref->shared_entry->dropped)
 		return;
 
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index 1877d22f146..f87a195996a 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -77,6 +77,7 @@ AtEOXact_PgStat_DroppedStats(PgStat_SubXactStatus *xact_state, bool isCommit)
 		PgStat_PendingDroppedStatsItem *pending =
 			dclist_container(PgStat_PendingDroppedStatsItem, node, iter.cur);
 		xl_xact_stats_item *it = &pending->item;
+		uint64		objid = ((uint64) it->objid_hi) << 32 | it->objid_lo;
 
 		if (isCommit && !pending->is_create)
 		{
@@ -84,7 +85,7 @@ AtEOXact_PgStat_DroppedStats(PgStat_SubXactStatus *xact_state, bool isCommit)
 			 * Transaction that dropped an object committed. Drop the stats
 			 * too.
 			 */
-			if (!pgstat_drop_entry(it->kind, it->dboid, it->objoid))
+			if (!pgstat_drop_entry(it->kind, it->dboid, objid))
 				not_freed_count++;
 		}
 		else if (!isCommit && pending->is_create)
@@ -93,7 +94,7 @@ AtEOXact_PgStat_DroppedStats(PgStat_SubXactStatus *xact_state, bool isCommit)
 			 * Transaction that created an object aborted. Drop the stats
 			 * associated with the object.
 			 */
-			if (!pgstat_drop_entry(it->kind, it->dboid, it->objoid))
+			if (!pgstat_drop_entry(it->kind, it->dboid, objid))
 				not_freed_count++;
 		}
 
@@ -149,6 +150,7 @@ AtEOSubXact_PgStat_DroppedStats(PgStat_SubXactStatus *xact_state,
 		PgStat_PendingDroppedStatsItem *pending =
 			dclist_container(PgStat_PendingDroppedStatsItem, node, iter.cur);
 		xl_xact_stats_item *it = &pending->item;
+		uint64		objid = ((uint64) it->objid_hi) << 32 | it->objid_lo;
 
 		dclist_delete_from(&xact_state->pending_drops, &pending->node);
 
@@ -158,7 +160,7 @@ AtEOSubXact_PgStat_DroppedStats(PgStat_SubXactStatus *xact_state,
 			 * Subtransaction creating a new stats object aborted. Drop the
 			 * stats object.
 			 */
-			if (!pgstat_drop_entry(it->kind, it->dboid, it->objoid))
+			if (!pgstat_drop_entry(it->kind, it->dboid, objid))
 				not_freed_count++;
 			pfree(pending);
 		}
@@ -319,8 +321,9 @@ pgstat_execute_transactional_drops(int ndrops, struct xl_xact_stats_item *items,
 	for (int i = 0; i < ndrops; i++)
 	{
 		xl_xact_stats_item *it = &items[i];
+		uint64		objid = ((uint64) it->objid_hi) << 32 | it->objid_lo;
 
-		if (!pgstat_drop_entry(it->kind, it->dboid, it->objoid))
+		if (!pgstat_drop_entry(it->kind, it->dboid, objid))
 			not_freed_count++;
 	}
 
@@ -329,7 +332,7 @@ pgstat_execute_transactional_drops(int ndrops, struct xl_xact_stats_item *items,
 }
 
 static void
-create_drop_transactional_internal(PgStat_Kind kind, Oid dboid, Oid objoid, bool is_create)
+create_drop_transactional_internal(PgStat_Kind kind, Oid dboid, uint64 objid, bool is_create)
 {
 	int			nest_level = GetCurrentTransactionNestLevel();
 	PgStat_SubXactStatus *xact_state;
@@ -341,7 +344,8 @@ create_drop_transactional_internal(PgStat_Kind kind, Oid dboid, Oid objoid, bool
 	drop->is_create = is_create;
 	drop->item.kind = kind;
 	drop->item.dboid = dboid;
-	drop->item.objoid = objoid;
+	drop->item.objid_lo = (uint32) objid;
+	drop->item.objid_hi = (uint32) (objid >> 32);
 
 	dclist_push_tail(&xact_state->pending_drops, &drop->node);
 }
@@ -354,18 +358,19 @@ create_drop_transactional_internal(PgStat_Kind kind, Oid dboid, Oid objoid, bool
  * dropped.
  */
 void
-pgstat_create_transactional(PgStat_Kind kind, Oid dboid, Oid objoid)
+pgstat_create_transactional(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
-	if (pgstat_get_entry_ref(kind, dboid, objoid, false, NULL))
+	if (pgstat_get_entry_ref(kind, dboid, objid, false, NULL))
 	{
 		ereport(WARNING,
-				errmsg("resetting existing statistics for kind %s, db=%u, oid=%u",
-					   (pgstat_get_kind_info(kind))->name, dboid, objoid));
+				errmsg("resetting existing statistics for kind %s, db=%u, oid=%llu",
+					   (pgstat_get_kind_info(kind))->name, dboid,
+					   (unsigned long long) objid));
 
-		pgstat_reset(kind, dboid, objoid);
+		pgstat_reset(kind, dboid, objid);
 	}
 
-	create_drop_transactional_internal(kind, dboid, objoid, /* create */ true);
+	create_drop_transactional_internal(kind, dboid, objid, /* create */ true);
 }
 
 /*
@@ -376,7 +381,7 @@ pgstat_create_transactional(PgStat_Kind kind, Oid dboid, Oid objoid)
  * alive.
  */
 void
-pgstat_drop_transactional(PgStat_Kind kind, Oid dboid, Oid objoid)
+pgstat_drop_transactional(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
-	create_drop_transactional_internal(kind, dboid, objoid, /* create */ false);
+	create_drop_transactional_internal(kind, dboid, objid, /* create */ false);
 }
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 33c7b25560b..9c23ac7c8c8 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -2046,8 +2046,8 @@ pg_stat_have_stats(PG_FUNCTION_ARGS)
 {
 	char	   *stats_type = text_to_cstring(PG_GETARG_TEXT_P(0));
 	Oid			dboid = PG_GETARG_OID(1);
-	Oid			objoid = PG_GETARG_OID(2);
+	uint64		objid = PG_GETARG_INT64(2);
 	PgStat_Kind kind = pgstat_get_kind_from_str(stats_type);
 
-	PG_RETURN_BOOL(pgstat_have_entry(kind, dboid, objoid));
+	PG_RETURN_BOOL(pgstat_have_entry(kind, dboid, objid));
 }