RelationClearRelation must reset rd_targblock and update rd_nblocks

tglsfdc · tglsfdc · commit 3503f19eeb81 · 2002-09-22T20:56:28.000Z
even when dealing with a nailed-in-cache relation; otherwise, following
VACUUM truncation of a system catalog, other backends might have
unreasonably large values of these fields.
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.175 2002/09/04 20:31:30 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.176 2002/09/22 20:56:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1685,10 +1685,14 @@ RelationClearRelation(Relation relation, bool rebuild)
 
 	/*
 	 * Never, never ever blow away a nailed-in system relation, because
-	 * we'd be unable to recover.
+	 * we'd be unable to recover.  However, we must update rd_nblocks
+	 * and reset rd_targblock, in case we got called because of a relation
+	 * cache flush that was triggered by VACUUM.
 	 */
 	if (relation->rd_isnailed)
 	{
+		relation->rd_targblock = InvalidBlockNumber;
+		RelationUpdateNumberOfBlocks(relation);
 #ifdef	ENABLE_REINDEX_NAILED_RELATIONS
 		RelationReloadClassinfo(relation);
 #endif   /* ENABLE_REINDEX_NAILED_RELATIONS */

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.175 2002/09/04 20:31:30 momjian Exp $`
	`11`	`+ * $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.176 2002/09/22 20:56:28 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -1685,10 +1685,14 @@ RelationClearRelation(Relation relation, bool rebuild)`
`1685`	`1685`
`1686`	`1686`	`/*`
`1687`	`1687`	`* Never, never ever blow away a nailed-in system relation, because`
`1688`		`- * we'd be unable to recover.`
	`1688`	`+ * we'd be unable to recover. However, we must update rd_nblocks`
	`1689`	`+ * and reset rd_targblock, in case we got called because of a relation`
	`1690`	`+ * cache flush that was triggered by VACUUM.`
`1689`	`1691`	`*/`
`1690`	`1692`	`if (relation->rd_isnailed)`
`1691`	`1693`	`{`
	`1694`	`+ relation->rd_targblock = InvalidBlockNumber;`
	`1695`	`+ RelationUpdateNumberOfBlocks(relation);`
`1692`	`1696`	`#ifdef ENABLE_REINDEX_NAILED_RELATIONS`
`1693`	`1697`	`RelationReloadClassinfo(relation);`
`1694`	`1698`	`#endif /* ENABLE_REINDEX_NAILED_RELATIONS */`