Calculation of keys_are_unique flag was wrong for cases involving

redundant cross-datatype comparisons.  Per example from Merlin Moncure.

diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index bd640f6f8b5aba72276c58451f925d836c9dedb3..03b9cf080cac6ebb4310467481f8c1e1ac3af5f2 100644 (file)
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/access/nbtree/nbtutils.c,v 1.60 2004/08/29 05:06:40 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/access/nbtree/nbtutils.c,v 1.61 2004/12/15 19:16:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -224,11 +224,11 @@ _bt_preprocess_keys(IndexScanDesc scan)
    BTScanOpaque so = (BTScanOpaque) scan->opaque;
    int         numberOfKeys = scan->numberOfKeys;
    int         new_numberOfKeys;
+   int         numberOfEqualCols;
    ScanKey     inkeys;
    ScanKey     outkeys;
    ScanKey     cur;
    ScanKey     xform[BTMaxStrategyNumber];
-   bool        allEqualSoFar;
    bool        hasOtherTypeEqual;
    Datum       test;
    int         i,
@@ -278,7 +278,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
     * Otherwise, do the full set of pushups.
     */
    new_numberOfKeys = 0;
-   allEqualSoFar = true;
+   numberOfEqualCols = 0;
 
    /*
     * Initialize for processing of keys for attr 1.
@@ -321,7 +321,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
         */
        if (i == numberOfKeys || cur->sk_attno != attno)
        {
-           bool        priorAllEqualSoFar = allEqualSoFar;
+           int         priorNumberOfEqualCols = numberOfEqualCols;
 
            /* check input keys are correctly ordered */
            if (i < numberOfKeys && cur->sk_attno != attno + 1)
@@ -355,14 +355,14 @@ _bt_preprocess_keys(IndexScanDesc scan)
                xform[BTLessEqualStrategyNumber - 1] = NULL;
                xform[BTGreaterEqualStrategyNumber - 1] = NULL;
                xform[BTGreaterStrategyNumber - 1] = NULL;
+               /* track number of attrs for which we have "=" keys */
+               numberOfEqualCols++;
            }
            else
            {
-               /*
-                * If no "=" for this key, we're done with required keys
-                */
-               if (!hasOtherTypeEqual)
-                   allEqualSoFar = false;
+               /* track number of attrs for which we have "=" keys */
+               if (hasOtherTypeEqual)
+                   numberOfEqualCols++;
            }
 
            /* keep only one of <, <= */
@@ -411,7 +411,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
             * If all attrs before this one had "=", include these keys
             * into the required-keys count.
             */
-           if (priorAllEqualSoFar)
+           if (priorNumberOfEqualCols == attno - 1)
                so->numberOfRequiredKeys = new_numberOfKeys;
 
            /*
@@ -468,8 +468,8 @@ _bt_preprocess_keys(IndexScanDesc scan)
     * If unique index and we have equality keys for all columns, set
     * keys_are_unique flag for higher levels.
     */
-   if (allEqualSoFar && relation->rd_index->indisunique &&
-       relation->rd_rel->relnatts == new_numberOfKeys)
+   if (relation->rd_index->indisunique &&
+       relation->rd_rel->relnatts == numberOfEqualCols)
        scan->keys_are_unique = true;
 }