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Code Activity

Fixed MDEV-5424: SELECT using ORDER BY DESC and LIMIT produces unexpected results (InnoDB/XtraDB)

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This only happend when using an ORDER BY on a primary key part, where all other key parts where constant.
Remove of duplicated expressions in ORDER BY (as the old code did this in some strange cases)


mysql-test/r/group_by.result:
  Fixed results to take into account that duplicate order by parts are now deleted
mysql-test/r/group_by_innodb.result:
  Ensure extended keys are on
mysql-test/r/innodb_ext_key.result:
  More tests
mysql-test/r/order_by.result:
  More tests
mysql-test/t/group_by.test:
  Fixed results to take into account that duplicate order by parts are now deleted
mysql-test/t/group_by_innodb.test:
  Ensure extended keys are on
mysql-test/t/innodb_ext_key.test:
  More tests
mysql-test/t/order_by.test:
  More tests
sql/sql_select.cc:
  Fixed bug where we looked at extended key parts when we shouldn't
  Remove of duplicated expressions in ORDER BY
sql/table.cc:
  Indentation fixes
This commit is contained in:
Michael Widenius
2014-01-02 15:51:02 +02:00
parent f8c7e3477f
commit c050b5fdf9
10 changed files with 149 additions and 37 deletions
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48
mysql-test/r/innodb_ext_key.result
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@ -987,6 +987,54 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref page_timestamp page_timestamp 4 const 10 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.rev_text_id 1
DROP TABLE t1,t2,t3;
#
# MDEV-5424 SELECT using ORDER BY DESC and LIMIT produces unexpected
# results (InnoDB/XtraDB)
#
create table t1 (a bigint not null unique auto_increment, b varchar(10), primary key (a), key (b(2))) engine = myisam default character set utf8;
create table t2 (a bigint not null unique auto_increment, b varchar(10), primary key (a), key (b(2))) engine = innodb default character set utf8;
insert into t1 (b) values (null), (null), (null);
insert into t2 (b) values (null), (null), (null);
set optimizer_switch='extended_keys=on';
explain select a from t1 where b is null order by a desc limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref b b 9 const 2 Using where; Using filesort
select a from t1 where b is null order by a desc limit 2;
a
3
2
explain select a from t2 where b is null order by a desc limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range b b 9 NULL 3 Using where; Using filesort
select a from t2 where b is null order by a desc limit 2;
a
3
2
set optimizer_switch='extended_keys=off';
explain select a from t2 where b is null order by a desc limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range b b 9 NULL 3 Using where; Using filesort
select a from t2 where b is null order by a desc limit 2;
a
3
2
explain select a from t2 where b is null order by a desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index b PRIMARY 8 NULL 3 Using where
select a from t2 where b is null order by a desc;
a
3
2
1
explain select a from t2 where b is null order by a desc,a,a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index b PRIMARY 8 NULL 3 Using where
select a from t2 where b is null order by a desc,a,a;
a
3
2
1
drop table t1, t2;
set optimizer_switch=@save_optimizer_switch;
set optimizer_switch=@save_ext_key_optimizer_switch;
SET SESSION STORAGE_ENGINE=DEFAULT;