Fix nasty little order-of-operations bug in _SPI_cursor_operation.

Per report from Mendola Gaetano.

diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 064f64c..985b966 100644 (file)
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.101 2003/08/04 02:39:59 momjian Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.102 2003/08/08 19:18:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1263,6 +1263,8 @@ static void
 _SPI_cursor_operation(Portal portal, bool forward, int count,
                                          DestReceiver *dest)
 {
+       long    nfetched;
+
        /* Check that the portal is valid */
        if (!PortalIsValid(portal))
                elog(ERROR, "invalid portal in SPI cursor operation");
@@ -1277,11 +1279,20 @@ _SPI_cursor_operation(Portal portal, bool forward, int count,
        _SPI_current->tuptable = NULL;
 
        /* Run the cursor */
-       _SPI_current->processed =
-               PortalRunFetch(portal,
-                                          forward ? FETCH_FORWARD : FETCH_BACKWARD,
-                                          (long) count,
-                                          dest);
+       nfetched = PortalRunFetch(portal,
+                                                         forward ? FETCH_FORWARD : FETCH_BACKWARD,
+                                                         (long) count,
+                                                         dest);
+
+       /*
+        * Think not to combine this store with the preceding function call.
+        * If the portal contains calls to functions that use SPI, then
+        * SPI_stack is likely to move around while the portal runs.  When
+        * control returns, _SPI_current will point to the correct stack entry...
+        * but the pointer may be different than it was beforehand.  So we must
+        * be sure to re-fetch the pointer after the function call completes.
+        */
+       _SPI_current->processed = nfetched;
 
        if (dest->mydest == SPI && _SPI_checktuples())
                elog(ERROR, "consistency check on SPI tuple count failed");