Fix a many-legged critter reported by chifungfan@yahoo.com: under the

right circumstances a hash join executed as a DECLARE CURSOR/FETCH
query would crash the backend.  Problem as seen in current sources was
that the hash tables were stored in a context that was a child of
TransactionCommandContext, which got zapped at completion of the FETCH
command --- but cursor cleanup executed at COMMIT expected the tables
to still be valid.  I haven't chased down the details as seen in 7.0.*
but I'm sure it's the same general problem.

2 files changed, 10 insertions, 5 deletions

diff --git a/src/include/executor/hashjoin.h b/src/include/executor/hashjoin.h
index 8d4cb98469f..25a8174f294 100644
--- a/src/include/executor/hashjoin.h
+++ b/src/include/executor/hashjoin.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: hashjoin.h,v 1.18 2000/07/12 02:37:30 tgl Exp $
+ * $Id: hashjoin.h,v 1.19 2000/08/22 04:06:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -26,7 +26,7 @@
  * This makes it easy and fast to release the storage when we don't need it
  * anymore.
  *
- * The contexts are made children of TransactionCommandContext, ensuring
+ * The hashtable contexts are made children of the per-query context, ensuring
  * that they will be discarded at end of statement even if the join is
  * aborted early by an error.  (Likewise, any temporary files we make will
  * be cleaned up by the virtual file manager in event of an error.)
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 6e691c1d786..1ec14f4a969 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: execnodes.h,v 1.46 2000/08/13 02:50:24 tgl Exp $
+ * $Id: execnodes.h,v 1.47 2000/08/22 04:06:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -223,9 +223,14 @@ typedef struct EState
 	uint32		es_processed;	/* # of tuples processed */
 	Oid			es_lastoid;		/* last oid processed (by INSERT) */
 	List	   *es_rowMark;		/* not good place, but there is no other */
-	/* these two fields are storage space for ExecConstraints(): */
+	MemoryContext es_query_cxt;	/* per-query context in which EState lives */
+	/* this ExprContext is for per-output-tuple operations, such as
+	 * constraint checks and index-value computations.  It can be reset
+	 * for each output tuple.  Note that it will be created only if needed.
+	 */
+	ExprContext *es_per_tuple_exprcontext;
+	/* this field is storage space for ExecConstraints(): */
 	List	  **es_result_relation_constraints;
-	ExprContext *es_constraint_exprcontext;
 	/* Below is to re-evaluate plan qual in READ COMMITTED mode */
 	struct Plan *es_origPlan;
 	Pointer		es_evalPlanQual;