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4.1->5.0 merge for bug #16458

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mysql-test/r/distinct.result:
  4.1->5.0 merge for bug #16458
   * 5.0 is better in detecting duplicate columns
sql/sql_select.cc:
  4.1->5.0 merge for bug #16458
   * Should not do the optimization if using index for group by
   * chnaged structures in 5.0
This commit is contained in:
unknown
2006-06-28 15:53:54 +03:00
parent 6a4ec2e99d
commit 8f42d836dc
2 changed files with 8 additions and 4 deletions
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2
mysql-test/r/distinct.result
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@ -537,7 +537,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL PRIMARY 8 NULL 3 Using index
EXPLAIN SELECT DISTINCT a,a FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL PRIMARY 8 NULL 3 Using index; Using temporary
1 SIMPLE t2 index NULL PRIMARY 8 NULL 3 Using index
EXPLAIN SELECT DISTINCT b,a FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL PRIMARY 8 NULL 3 Using index

10
sql/sql_select.cc
View File

@ -874,7 +874,11 @@ JOIN::optimize()
The FROM clause must contain a single non-constant table.
*/
if (tables - const_tables == 1 && (group_list || select_distinct) &&
!tmp_table_param.sum_func_count)
!tmp_table_param.sum_func_count &&
(!join_tab[const_tables].select ||
!join_tab[const_tables].select->quick ||
join_tab[const_tables].select->quick->get_type() !=
QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX))
{
if (group_list &&
list_contains_unique_index(join_tab[const_tables].table,
@ -11279,9 +11283,9 @@ static bool
list_contains_unique_index(TABLE *table,
bool (*find_func) (Field *, void *), void *data)
{
for (uint keynr= 0; keynr < table->keys; keynr++)
for (uint keynr= 0; keynr < table->s->keys; keynr++)
{
if (keynr == table->primary_key ||
if (keynr == table->s->primary_key ||
(table->key_info[keynr].flags & HA_NOSAME))
{
KEY *keyinfo= table->key_info + keynr;