From 4863829c1291b16fca7b166d3b9db0668bee4f63 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 4 Jun 2000 22:08:53 +0000
Subject: [PATCH] If user re-DECLAREs an existing cursor name, close the old
 cursor of that name and issue a NOTICE to the effect that we did. 
 Previously, code would try to assign the new cursor declaration to the old
 portal, but this didn't work reliably since new parsetree is still sitting in
 blank portal and is likely to get clobbered.

---
 src/backend/tcop/pquery.c | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index dfc0f4e892..aa2b8e2c06 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -8,20 +8,19 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/pquery.c,v 1.31 2000/06/04 01:44:33 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/pquery.c,v 1.32 2000/06/04 22:08:53 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 
 #include "postgres.h"
 
+#include "commands/command.h"
 #include "executor/execdefs.h"
 #include "executor/executor.h"
 #include "tcop/pquery.h"
 #include "utils/ps_status.h"
 
-#include "commands/command.h"
-
 static char *CreateOperationTag(int operationType);
 static void ProcessQueryDesc(QueryDesc *queryDesc, Node *limoffset,
 				 Node *limcount);
@@ -140,15 +139,32 @@ ProcessPortal(char *portalName,
 	MemoryContext portalContext;
 
 	/* ----------------
-	 *	 convert the current blank portal into the user-specified
-	 *	 portal and initialize the state and query descriptor.
+	 *	 Check for reserved or already-in-use portal name.
 	 * ----------------
 	 */
 
 	if (PortalNameIsSpecial(portalName))
 		elog(ERROR,
-			 "The portal name %s is reserved for internal use",
+			 "The portal name \"%s\" is reserved for internal use",
+			 portalName);
+
+	portal = GetPortalByName(portalName);
+	if (PortalIsValid(portal))
+	{
+		/* XXX Should we raise an error rather than closing the old portal? */
+		elog(NOTICE, "Closing pre-existing portal \"%s\"",
 			 portalName);
+		PortalDrop(&portal);
+	}
+
+	/* ----------------
+	 *	 Convert the current blank portal into the user-specified
+	 *	 portal and initialize the state and query descriptor.
+	 *
+	 *	 Since the parsetree has been created in the current blank portal,
+	 *	 we don't have to do any work to copy it into the user-named portal.
+	 * ----------------
+	 */
 
 	portal = BlankPortalAssignName(portalName);
 
@@ -159,8 +175,8 @@ ProcessPortal(char *portalName,
 				   PortalCleanup);
 
 	/* ----------------
-	 *	now create a new blank portal and switch to it.
-	 *	Otherwise, the new named portal will be cleaned.
+	 *	Now create a new blank portal and switch to it.
+	 *	Otherwise, the new named portal will be cleaned at statement end.
 	 *
 	 *	Note: portals will only be supported within a BEGIN...END
 	 *	block in the near future.  Later, someone will fix it to
-- 
GitLab