Defend against brain-dead QNX implementation of qsort().

Per report from Bernd Tegge, 10-Nov-01.

diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c
index 796be9d..ad937c9 100644 (file)
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -78,7 +78,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/utils/sort/tuplesort.c,v 1.20 2001/10/28 06:25:57 momjian Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/utils/sort/tuplesort.c,v 1.21 2001/11/11 22:00:25 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1881,8 +1881,13 @@ comparetup_index(Tuplesortstate *state, const void *a, const void *b)
         * equal they *must* get compared at some stage of the sort ---
         * otherwise the sort algorithm wouldn't have checked whether one must
         * appear before the other.
+        *
+        * Some rather brain-dead implementations of qsort will sometimes
+        * call the comparison routine to compare a value to itself.  (At this
+        * writing only QNX 4 is known to do such silly things.)  Don't raise
+        * a bogus error in that case.
         */
-       if (state->enforceUnique && !equal_hasnull)
+       if (state->enforceUnique && !equal_hasnull && tuple1 != tuple2)
                elog(ERROR, "Cannot create unique index. Table contains non-unique values");
 
        return 0;