Back-patch fix for erroneous selectivity of not-equals.

diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 4718dc668a7313fb5a21d6b50c666f0360acf733..246a8d6086d23974846563ace02a9a7ac0bb16c1 100644 (file)
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.66 2000/05/26 17:19:15 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.66.2.1 2000/09/23 21:27:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -255,9 +255,24 @@ neqsel(Oid opid,
       Datum value,
       int32 flag)
 {
+   Oid         eqopid;
    float64     result;
 
-   result = eqsel(opid, relid, attno, value, flag);
+   /*
+    * We want 1 - eqsel() where the equality operator is the one associated
+    * with this != operator, that is, its negator.
+    */
+   eqopid = get_negator(opid);
+   if (eqopid)
+   {
+       result = eqsel(eqopid, relid, attno, value, flag);
+   }
+   else
+   {
+       /* Use default selectivity (should we raise an error instead?) */
+       result = (float64) palloc(sizeof(float64data));
+       *result = DEFAULT_EQ_SEL;
+   }
    *result = 1.0 - *result;
    return result;
 }