Fix varstr_cmp's special case for UTF8 encoding on Windows so that strings

that are reported as "equal" by wcscoll() are checked to see if they really
are bitwise equal, and are sorted per strcmp() if not.  We made this happen
a couple of years ago in the regular code path, but it unaccountably got
left out of the Windows/UTF8 case (probably brain fade on my part at the
time).  As in the prior set of changes, affected users may need to reindex
indexes on textual columns.

Backpatch as far as 8.2, which is the oldest release we are still supporting
on Windows.

diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index d96890f425e9910a1a2c6bee89c194ce6c1e7ec2..f88c9b21fa00e744f85fb6063d1f23c7977c4f3f 100644 (file)
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.153.2.1 2007/07/19 20:34:27 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.153.2.2 2008/03/13 18:32:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1002,6 +1002,19 @@ varstr_cmp(char *arg1, int len1, char *arg2, int len2)
                                ereport(ERROR,
                                                (errmsg("could not compare Unicode strings: %m")));
 
+                       /*
+                        * In some locales wcscoll() can claim that nonidentical strings
+                        * are equal.  Believing that would be bad news for a number of
+                        * reasons, so we follow Perl's lead and sort "equal" strings
+                        * according to strcmp (on the UTF-8 representation).
+                        */
+                       if (result == 0)
+                       {
+                               result = strncmp(arg1, arg2, Min(len1, len2));
+                               if ((result == 0) && (len1 != len2))
+                                       result = (len1 < len2) ? -1 : 1;
+                       }
+
                        if (a1p != a1buf)
                                pfree(a1p);
                        if (a2p != a2buf)