Use a shutdown callback to ensure proper clean up when rescanning

partially-evaluated SRFs. Per report found here:
http://archives.postgresql.org/pgsql-general/2003-12/msg00851.php

diff --git a/src/backend/utils/fmgr/funcapi.c b/src/backend/utils/fmgr/funcapi.c
index 591e68f..e6ef3fc 100644 (file)
--- a/src/backend/utils/fmgr/funcapi.c
+++ b/src/backend/utils/fmgr/funcapi.c
@@ -7,7 +7,7 @@
  * Copyright (c) 2002-2003, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/fmgr/funcapi.c,v 1.12 2003/11/29 19:52:01 pgsql Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/fmgr/funcapi.c,v 1.13 2003/12/19 00:02:11 joe Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,6 +17,7 @@
 #include "catalog/pg_type.h"
 #include "utils/syscache.h"
 
+static void shutdown_MultiFuncCall(Datum arg);
 
 /*
  * init_MultiFuncCall
@@ -41,7 +42,10 @@ init_MultiFuncCall(PG_FUNCTION_ARGS)
        {
                /*
                 * First call
-                *
+                */
+               ReturnSetInfo      *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
+
+               /*
                 * Allocate suitably long-lived space and zero it
                 */
                retval = (FuncCallContext *)
@@ -63,6 +67,14 @@ init_MultiFuncCall(PG_FUNCTION_ARGS)
                 * save the pointer for cross-call use
                 */
                fcinfo->flinfo->fn_extra = retval;
+
+               /*
+                * Ensure we will get shut down cleanly if the exprcontext is not
+                * run to completion.
+                */
+               RegisterExprContextCallback(rsi->econtext,
+                                                                       shutdown_MultiFuncCall,
+                                                                       PointerGetDatum(fcinfo->flinfo));
        }
        else
        {
@@ -108,8 +120,29 @@ per_MultiFuncCall(PG_FUNCTION_ARGS)
 void
 end_MultiFuncCall(PG_FUNCTION_ARGS, FuncCallContext *funcctx)
 {
-       /* unbind from fcinfo */
-       fcinfo->flinfo->fn_extra = NULL;
+       ReturnSetInfo      *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
+
+       /* Deregister the shutdown callback */
+       UnregisterExprContextCallback(rsi->econtext,
+                                                                 shutdown_MultiFuncCall,
+                                                                 PointerGetDatum(fcinfo->flinfo));
+
+       /* But use it to do the real work */
+       shutdown_MultiFuncCall(PointerGetDatum(fcinfo->flinfo));
+}
+
+/*
+ * shutdown_MultiFuncCall
+ * Shutdown function to clean up after init_MultiFuncCall
+ */
+static void
+shutdown_MultiFuncCall(Datum arg)
+{
+       FmgrInfo *flinfo = (FmgrInfo *) DatumGetPointer(arg);
+       FuncCallContext *funcctx = (FuncCallContext *) flinfo->fn_extra;
+
+       /* unbind from flinfo */
+       flinfo->fn_extra = NULL;
 
        /*
         * Caller is responsible to free up memory for individual struct