Commit 8f42d836 authored by unknown's avatar unknown
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4.1->5.0 merge for bug #16458 


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
parent 6a4ec2e9

mysql-test/r/distinct.result

+1 −1
Original line number Diff line number Diff line
@@ -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

sql/sql_select.cc

+7 −3
Original line number Diff line number Diff line
@@ -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;