Fix nodeTidscan.c to not trigger an error if the block number portion of

tglsfdc · tglsfdc · commit 772f63dd6a4d · 2008-04-30T23:28:32.000Z
a user-supplied TID is out of range for the relation.  This is needed to
preserve compatibility with our pre-8.3 behavior, and it is sensible anyway
since if the query were implemented by brute force rather than optimized
into a TidScan, the behavior for a non-existent TID would be zero rows out,
never an error.  Per gripe from Gurjeet Singh.
diff --git a/src/backend/executor/nodeTidscan.c b/src/backend/executor/nodeTidscan.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.58 2008/01/01 19:45:49 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.59 2008/04/30 23:28:32 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -54,11 +54,20 @@ TidListCreate(TidScanState *tidstate)
 {
 	List	   *evalList = tidstate->tss_tidquals;
 	ExprContext *econtext = tidstate->ss.ps.ps_ExprContext;
+	BlockNumber nblocks;
 	ItemPointerData *tidList;
 	int			numAllocTids;
 	int			numTids;
 	ListCell   *l;
 
+	/*
+	 * We silently discard any TIDs that are out of range at the time of
+	 * scan start.  (Since we hold at least AccessShareLock on the table,
+	 * it won't be possible for someone to truncate away the blocks we
+	 * intend to visit.)
+	 */
+	nblocks = RelationGetNumberOfBlocks(tidstate->ss.ss_currentRelation);
+
 	/*
 	 * We initialize the array with enough slots for the case that all quals
 	 * are simple OpExprs or CurrentOfExprs.  If there are any
@@ -97,7 +106,9 @@ TidListCreate(TidScanState *tidstate)
 														  econtext,
 														  &isNull,
 														  NULL));
-			if (!isNull && ItemPointerIsValid(itemptr))
+			if (!isNull &&
+				ItemPointerIsValid(itemptr) &&
+				ItemPointerGetBlockNumber(itemptr) < nblocks)
 			{
 				if (numTids >= numAllocTids)
 				{
@@ -142,7 +153,8 @@ TidListCreate(TidScanState *tidstate)
 				if (!ipnulls[i])
 				{
 					itemptr = (ItemPointer) DatumGetPointer(ipdatums[i]);
-					if (ItemPointerIsValid(itemptr))
+					if (ItemPointerIsValid(itemptr) &&
+						ItemPointerGetBlockNumber(itemptr) < nblocks)
 						tidList[numTids++] = *itemptr;
 				}
 			}

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.58 2008/01/01 19:45:49 momjian Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.59 2008/04/30 23:28:32 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -54,11 +54,20 @@ TidListCreate(TidScanState *tidstate)`
`54`	`54`	`{`
`55`	`55`	`List *evalList = tidstate->tss_tidquals;`
`56`	`56`	`ExprContext *econtext = tidstate->ss.ps.ps_ExprContext;`
	`57`	`+ BlockNumber nblocks;`
`57`	`58`	`ItemPointerData *tidList;`
`58`	`59`	`int numAllocTids;`
`59`	`60`	`int numTids;`
`60`	`61`	`ListCell *l;`
`61`	`62`
	`63`	`+ /*`
	`64`	`+ * We silently discard any TIDs that are out of range at the time of`
	`65`	`+ * scan start. (Since we hold at least AccessShareLock on the table,`
	`66`	`+ * it won't be possible for someone to truncate away the blocks we`
	`67`	`+ * intend to visit.)`
	`68`	`+ */`
	`69`	`+ nblocks = RelationGetNumberOfBlocks(tidstate->ss.ss_currentRelation);`
	`70`	`+`
`62`	`71`	`/*`
`63`	`72`	`* We initialize the array with enough slots for the case that all quals`
`64`	`73`	`* are simple OpExprs or CurrentOfExprs. If there are any`
`@@ -97,7 +106,9 @@ TidListCreate(TidScanState *tidstate)`
`97`	`106`	`econtext,`
`98`	`107`	`&isNull,`
`99`	`108`	`NULL));`
`100`		`- if (!isNull && ItemPointerIsValid(itemptr))`
	`109`	`+ if (!isNull &&`
	`110`	`+ ItemPointerIsValid(itemptr) &&`
	`111`	`+ ItemPointerGetBlockNumber(itemptr) < nblocks)`
`101`	`112`	`{`
`102`	`113`	`if (numTids >= numAllocTids)`
`103`	`114`	`{`
`@@ -142,7 +153,8 @@ TidListCreate(TidScanState *tidstate)`
`142`	`153`	`if (!ipnulls[i])`
`143`	`154`	`{`
`144`	`155`	`itemptr = (ItemPointer) DatumGetPointer(ipdatums[i]);`
`145`		`- if (ItemPointerIsValid(itemptr))`
	`156`	`+ if (ItemPointerIsValid(itemptr) &&`
	`157`	`+ ItemPointerGetBlockNumber(itemptr) < nblocks)`
`146`	`158`	`tidList[numTids++] = *itemptr;`
`147`	`159`	`}`
`148`	`160`	`}`