Fix another place broken by new List implementation :-(. Per example

from goranpop@nspoint.net.  I think this escaped notice because in
simple cases the list is NIL on entry.

diff --git a/src/backend/optimizer/geqo/geqo_eval.c b/src/backend/optimizer/geqo/geqo_eval.c
index 90aa34fa5915e4fdb1d76ad385a525f5fbce3e6f..254fcd8956669717c687bd66621745d3cbeb9c25 100644 (file)
--- a/src/backend/optimizer/geqo/geqo_eval.c
+++ b/src/backend/optimizer/geqo/geqo_eval.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/optimizer/geqo/geqo_eval.c,v 1.71 2004/08/29 05:06:43 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/geqo/geqo_eval.c,v 1.72 2004/12/15 21:13:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -80,12 +80,17 @@ geqo_eval(Gene *tour, int num_gene, GeqoEvalData *evaldata)
        oldcxt = MemoryContextSwitchTo(mycontext);
 
        /*
-        * preserve root->join_rel_list, which gimme_tree changes; without
-        * this, it'll be pointing at recycled storage after the
-        * MemoryContextDelete below.
+        * gimme_tree will add entries to root->join_rel_list, which may or may
+        * not already contain some entries.  The newly added entries will be
+        * recycled by the MemoryContextDelete below, so we must ensure that
+        * the list is restored to its former state before exiting.  With the
+        * new List implementation, the easiest way is to make a duplicate list
+        * that gimme_tree can modify.
         */
        savelist = evaldata->root->join_rel_list;
 
+       evaldata->root->join_rel_list = list_copy(savelist);
+
        /* construct the best path for the given combination of relations */
        joinrel = gimme_tree(tour, num_gene, evaldata);