Commit b133be17 authored by unknown's avatar unknown
Browse files

Merge lamia.home:/home/timka/mysql/src/4.1-virgin 

into  lamia.home:/home/timka/mysql/src/4.1-bug-21787


sql/sql_select.cc:
  Auto merged
parents 49e2267e b017caef

mysql-test/r/limit.result

+14 −0
Original line number Diff line number Diff line
@@ -76,3 +76,17 @@ a 
a

1

drop table t1;

create table t1 (a int);

insert into t1 values (1),(2),(3),(4),(5),(6),(7);

explain select count(*) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	7	Using where; Using temporary

select count(*) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;

c

7

explain select sum(a) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	7	Using where; Using temporary

select sum(a) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;

c

28

mysql-test/t/limit.test

+10 −0
Original line number Diff line number Diff line
@@ -60,4 +60,14 @@ select 1 as a from t1 union all select 1 from dual limit 1; 
(select 1 as a from t1) union all (select 1 from dual) limit 1;

drop table t1;



#

# Bug #21787: COUNT(*) + ORDER BY + LIMIT returns wrong result

#

create table t1 (a int);

insert into t1 values (1),(2),(3),(4),(5),(6),(7);

explain select count(*) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;

select count(*) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;

explain select sum(a) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;

select sum(a) c FROM t1 WHERE a > 0 ORDER BY c LIMIT 3;



# End of 4.1 tests

sql/sql_select.cc

+14 −5
Original line number Diff line number Diff line
@@ -5616,11 +5616,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields, 
      keyinfo->key_length+=  key_part_info->length;

    }

  }

  else

  {

    set_if_smaller(table->max_rows, rows_limit);

    param->end_write_records= rows_limit;

  }



  if (distinct && field_count != param->hidden_field_count)

  {
@@ -5683,6 +5678,20 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields, 
	0 : FIELDFLAG_BINARY;

    }

  }



  /*

    Push the LIMIT clause to the temporary table creation, so that we

    materialize only up to 'rows_limit' records instead of all result records.

    This optimization is not applicable when there is GROUP BY or there is

    no GROUP BY, but there are aggregate functions, because both must be

    computed for all result rows.

  */

  if (!group && !thd->lex->current_select->with_sum_func)

  {

    set_if_smaller(table->max_rows, rows_limit);

    param->end_write_records= rows_limit;

  }



  if (thd->is_fatal_error)				// If end of memory

    goto err;					 /* purecov: inspected */

  table->db_record_offset=1;