diff options
Diffstat (limited to 'sql/opt_range.cc')
| -rw-r--r-- | sql/opt_range.cc | 36 |
1 files changed, 23 insertions, 13 deletions
diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 633fb3d571c..74ff9846383 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -11102,7 +11102,7 @@ static bool get_constant_key_infix(KEY *index_info, SEL_ARG *index_range_tree, uchar *key_infix, uint *key_infix_len, KEY_PART_INFO **first_non_infix_part); static bool -check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item, +check_group_min_max_predicates(Item *cond, Item_field *min_max_arg_item, Field::imagetype image_type); static void @@ -11676,13 +11676,16 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) */ static bool -check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item, +check_group_min_max_predicates(Item *cond, Item_field *min_max_arg_item, Field::imagetype image_type) { DBUG_ENTER("check_group_min_max_predicates"); DBUG_ASSERT(cond && min_max_arg_item); cond= cond->real_item(); + if (cond->get_cached_item()) + cond= cond->get_cached_item(); + Item::Type cond_type= cond->type(); if (cond_type == Item::COND_ITEM) /* 'AND' or 'OR' */ { @@ -11699,18 +11702,25 @@ check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item, } /* - TODO: - This is a very crude fix to handle sub-selects in the WHERE clause - (Item_subselect objects). With the test below we rule out from the - optimization all queries with subselects in the WHERE clause. What has to - be done, is that here we should analyze whether the subselect references - the MIN/MAX argument field, and disallow the optimization only if this is - so. + Disallow loose index scan if the MIN/MAX argument field is referenced by + a subquery in the WHERE clause. */ - if (cond_type == Item::SUBSELECT_ITEM || - (cond->get_cached_item() && - cond->get_cached_item()->type() == Item::SUBSELECT_ITEM)) - DBUG_RETURN(FALSE); + if (cond_type == Item::SUBSELECT_ITEM) + { + Item_subselect *subs_cond= (Item_subselect*) cond; + if (subs_cond->is_correlated) + { + DBUG_ASSERT(subs_cond->depends_on.elements > 0); + List_iterator_fast<Item*> li(subs_cond->depends_on); + Item **dep; + while ((dep= li++)) + { + if ((*dep)->eq(min_max_arg_item, FALSE)) + DBUG_RETURN(FALSE); + } + } + DBUG_RETURN(TRUE); + } /* Condition of the form 'field' is equivalent to 'field <> 0' and thus |