Prevent core dump when ExecMarkPos is called before any tuples have been

retrieved.  This cannot happen in ordinary execution, but it can happen
under EvalPlanQual().

diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index 7b96723844bd93f7450c6ad2e2a3df7f4831a1ad..a7cfce15b4cbee70ad136cc2b72ef78d588064b5 100644 (file)
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.75 2002/12/15 16:17:46 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.76 2002/12/18 00:14:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -470,10 +470,13 @@ ExecIndexMarkPos(IndexScanState *node)
        int                     indexPtr;
 
        indexPtr = node->iss_MarkIndexPtr = node->iss_IndexPtr;
-       indexScanDescs = node->iss_ScanDescs;
-       scanDesc = indexScanDescs[indexPtr];
+       if (indexPtr >= 0 && indexPtr < node->iss_NumIndices)
+       {
+               indexScanDescs = node->iss_ScanDescs;
+               scanDesc = indexScanDescs[indexPtr];
 
-       index_markpos(scanDesc);
+               index_markpos(scanDesc);
+       }
 }
 
 /* ----------------------------------------------------------------
@@ -482,8 +485,6 @@ ExecIndexMarkPos(IndexScanState *node)
  * old comments
  *             Restores scan position by restoring the current index.
  *             Returns nothing.
- *
- *             XXX Assumes previously marked scan position belongs to current index
  * ----------------------------------------------------------------
  */
 void
@@ -494,10 +495,13 @@ ExecIndexRestrPos(IndexScanState *node)
        int                     indexPtr;
 
        indexPtr = node->iss_IndexPtr = node->iss_MarkIndexPtr;
-       indexScanDescs = node->iss_ScanDescs;
-       scanDesc = indexScanDescs[indexPtr];
+       if (indexPtr >= 0 && indexPtr < node->iss_NumIndices)
+       {
+               indexScanDescs = node->iss_ScanDescs;
+               scanDesc = indexScanDescs[indexPtr];
 
-       index_restrpos(scanDesc);
+               index_restrpos(scanDesc);
+       }
 }
 
 /* ----------------------------------------------------------------