Merge mysql.com:/home/timka/mysql/src/5.0-virgin

into  mysql.com:/home/timka/mysql/src/5.0-bug-16710


mysql-test/r/group_min_max.result:
  Auto merged
mysql-test/t/group_min_max.test:
  Auto merged
sql/item.cc:
  Auto merged
sql/item.h:
  Auto merged
sql/opt_range.cc:
  Auto merged

1 files changed, 26 insertions, 0 deletions

diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 634c9db18a8..d76495a0678 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -6895,6 +6895,7 @@ cost_group_min_max(TABLE* table, KEY *index_info, uint used_key_parts,
                    bool have_min, bool have_max,
                    double *read_cost, ha_rows *records);
 
+
 /*
   Test if this access method is applicable to a GROUP query with MIN/MAX
   functions, and if so, construct a new TRP object.
@@ -7301,11 +7302,36 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree)
       }
       else if (min_max_arg_part &&
                (min_max_arg_part - first_non_group_part > 0))
+      {
         /*
           There is a gap but no range tree, thus no predicates at all for the
           non-group keyparts.
         */
         goto next_index;
+      }
+      else if (first_non_group_part && join->conds)
+      {
+        /*
+          If there is no MIN/MAX function in the query, but some index
+          key part is referenced in the WHERE clause, then this index
+          cannot be used because the WHERE condition over the keypart's
+          field cannot be 'pushed' to the index (because there is no
+          range 'tree'), and the WHERE clause must be evaluated before
+          GROUP BY/DISTINCT.
+        */
+        /*
+          Store the first and last keyparts that need to be analyzed
+          into one array that can be passed as parameter.
+        */
+        KEY_PART_INFO *key_part_range[2];
+        key_part_range[0]= first_non_group_part;
+        key_part_range[1]= last_part;
+
+        /* Check if cur_part is referenced in the WHERE clause. */
+        if (join->conds->walk(&Item::find_item_in_field_list_processor,
+                              (byte*) key_part_range))
+          goto next_index;
+      }
     }
 
     /*