Add a function to update the new pg_class cols

function is a copy of vac_update_relstats() but
just updating the columns relative to cache
statistics

2 files changed, 63 insertions, 0 deletions

diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 9606569617..b45f012f9c 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -1096,3 +1096,61 @@ vacuum_delay_point(void)
 		CHECK_FOR_INTERRUPTS();
 	}
 }
+
+
+/*
+ *	cache_update_relstats() -- update cache statistics for one relation
+ *
+ *  /!\ Same comment as function vac_update_relstats()
+ */
+void
+cache_update_relstats(Relation relation,
+					  float4 per_oscache, float4 per_pgcache,
+					  TransactionId frozenxid)
+{
+	Oid			relid = RelationGetRelid(relation);
+	Relation	rd;
+	HeapTuple	ctup;
+	Form_pg_class pgcform;
+	bool		dirty;
+
+	rd = heap_open(RelationRelationId, RowExclusiveLock);
+
+	/* Fetch a copy of the tuple to scribble on */
+	ctup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+	if (!HeapTupleIsValid(ctup))
+		elog(ERROR, "pg_class entry for relid %u vanished during cache analyze",
+			 relid);
+	pgcform = (Form_pg_class) GETSTRUCT(ctup);
+
+	/* Apply required updates, if any, to copied tuple */
+
+	dirty = false;
+	if (pgcform->reloscache != (float4) per_oscache)
+	{
+		pgcform->reloscache = (float4) per_oscache;
+		dirty = true;
+	}
+	if (pgcform->relpgcache != (float4) per_pgcache)
+	{
+		pgcform->relpgcache = (float4) per_pgcache;
+		dirty = true;
+	}
+
+	/*
+	 * relfrozenxid should never go backward.  Caller can pass
+	 * InvalidTransactionId if it has no new data.
+	 */
+	if (TransactionIdIsNormal(frozenxid) &&
+		TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid))
+	{
+		pgcform->relfrozenxid = frozenxid;
+		dirty = true;
+	}
+
+	/* If anything changed, write out the tuple. */
+	if (dirty)
+		heap_inplace_update(rd, ctup);
+
+	heap_close(rd, RowExclusiveLock);
+}
diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
index 79c9f5d90f..7f1801ab35 100644
--- a/src/include/commands/vacuum.h
+++ b/src/include/commands/vacuum.h
@@ -155,6 +155,11 @@ extern void vacuum_set_xid_limits(int freeze_min_age, int freeze_table_age,
 extern void vac_update_datfrozenxid(void);
 extern void vacuum_delay_point(void);
 
+extern void cache_update_relstats(Relation relation,
+								  float4 per_oscache,
+								  float4 per_pgcache,
+								  TransactionId frozenxid);
+
 /* in commands/vacuumlazy.c */
 extern void lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
 				BufferAccessStrategy bstrategy, bool *scanned_all);