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 591e68fcc96eb4e34d21aa4d307545b246261179..e6ef3fcec3c9e9c7e82c8d239436a3023fc0950e 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