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MDEV-6990 GROUP_MIN_MAX optimization is not applied in some cases when it could

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This commit is contained in:
Alexander Barkov
2015-03-12 18:12:15 +04:00
parent 129c82bb59
commit bb3115b256
6 changed files with 163 additions and 30 deletions
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34
sql/opt_range.cc
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@@ -13412,39 +13412,13 @@ check_group_min_max_predicates(Item *cond, Item_field *min_max_arg_item,
if (!simple_pred(pred, args, &inv))
DBUG_RETURN(FALSE);
/* Check for compatible string comparisons - similar to get_mm_leaf. */
if (args[0] && args[1] && !args[2]) // this is a binary function
{
if (args[1]->cmp_type() == TIME_RESULT &&
min_max_arg_item->field->cmp_type() != TIME_RESULT)
DBUG_ASSERT(pred->is_bool_type());
Item_bool_func *bool_func= (Item_bool_func*) pred;
if (!bool_func->can_optimize_group_min_max(min_max_arg_item,
args[1]))
DBUG_RETURN(FALSE);
/*
Can't use GROUP_MIN_MAX optimization for ENUM and SET,
because the values are stored as numbers in index,
while MIN() and MAX() work as strings.
It would return the records with min and max enum numeric indexes.
"Bug#45300 MAX() and ENUM type" should be fixed first.
*/
if (min_max_arg_item->field->real_type() == MYSQL_TYPE_ENUM ||
min_max_arg_item->field->real_type() == MYSQL_TYPE_SET)
DBUG_RETURN(FALSE);
if (min_max_arg_item->result_type() == STRING_RESULT &&
/*
Don't use an index when comparing strings of different collations.
*/
((args[1]->result_type() == STRING_RESULT &&
image_type == Field::itRAW &&
min_max_arg_item->field->charset() !=
pred->compare_collation()) ||
/*
We can't always use indexes when comparing a string index to a
number.
*/
(args[1]->result_type() != STRING_RESULT &&
min_max_arg_item->field->cmp_type() != args[1]->result_type())))
DBUG_RETURN(FALSE);
}
}
else