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mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00

Fixed optimizer bug in ORDER BY where some ORDER BY parts where ignored.

Extended default arguments to be up to 4095 characters
This commit is contained in:
monty@tik.mysql.fi
2001-07-30 22:49:39 +03:00
parent 1ebd29ac6e
commit 1731161ff4
5 changed files with 136 additions and 1042 deletions

View File

@ -111,3 +111,34 @@ DateOfAction TransactionID
member_id nickname voornaam
1
2
gid sid uid
104620 5 15
103867 5 27
103962 5 27
104619 5 75
104505 5 117
103853 5 250
gid sid uid
104620 5 15
103867 5 27
103962 5 27
104619 5 75
104505 5 117
103853 5 250
table type possible_keys key key_len ref rows Extra
t1 index PRIMARY PRIMARY 4 NULL 6 Using index
t2 eq_ref PRIMARY,uid PRIMARY 4 t1.gid 1
t3 eq_ref PRIMARY PRIMARY 2 t2.uid 1 where used; Using index
table type possible_keys key key_len ref rows Extra
t1 index PRIMARY PRIMARY 4 NULL 6 Using index
t3 eq_ref PRIMARY PRIMARY 2 t1.gid 1 where used
table type possible_keys key key_len ref rows Extra
t1 index PRIMARY PRIMARY 4 NULL 6 Using index; Using temporary; Using filesort
t2 eq_ref PRIMARY,uid PRIMARY 4 t1.gid 1
t3 eq_ref PRIMARY PRIMARY 2 t2.uid 1 where used; Using index
table type possible_keys key key_len ref rows Extra
t1 index PRIMARY PRIMARY 4 NULL 6 Using index; Using temporary; Using filesort
t3 eq_ref PRIMARY PRIMARY 2 t1.gid 1 where used
table type possible_keys key key_len ref rows Extra
t1 ALL NULL NULL NULL NULL 6 Using temporary; Using filesort
t3 eq_ref PRIMARY PRIMARY 2 t1.skr 1 where used

View File

@ -168,8 +168,8 @@ drop table t1,t2,t3;
#bug reported by Wouter de Jong
drop table if exists members;
CREATE TABLE members (
drop table if exists t1;
CREATE TABLE t1 (
member_id int(11) NOT NULL auto_increment,
inschrijf_datum varchar(20) NOT NULL default '',
lastchange_datum varchar(20) NOT NULL default '',
@ -200,8 +200,50 @@ CREATE TABLE members (
PRIMARY KEY (member_id)
) TYPE=MyISAM PACK_KEYS=1;
insert into members (member_id) values (1),(2),(3);
select member_id, nickname, voornaam FROM members
insert into t1 (member_id) values (1),(2),(3);
select member_id, nickname, voornaam FROM t1
ORDER by lastchange_datum DESC LIMIT 2;
drop table members;
drop table t1;
#
# Test optimizing bug with EQ_REF tables, where some ORDER BY parts where
# wrongly removed.
CREATE TABLE t1 (
gid int(10) unsigned NOT NULL auto_increment,
cid smallint(5) unsigned NOT NULL default '0',
PRIMARY KEY (gid),
KEY component_id (cid)
) TYPE=MyISAM;
INSERT INTO t1 VALUES (103853,108),(103867,108),(103962,108),(104505,108),(104619,108),(104620,108);
ALTER TABLE t1 add skr int(10) not null;
CREATE TABLE t2 (
gid int(10) unsigned NOT NULL default '0',
uid smallint(5) unsigned NOT NULL default '1',
sid tinyint(3) unsigned NOT NULL default '1',
PRIMARY KEY (gid),
KEY uid (uid),
KEY status_id (sid)
) TYPE=MyISAM;
INSERT INTO t2 VALUES (103853,250,5),(103867,27,5),(103962,27,5),(104505,117,5),(104619,75,5),(104620,15,5);
CREATE TABLE t3 (
uid smallint(6) NOT NULL auto_increment,
PRIMARY KEY (uid)
) TYPE=MyISAM;
INSERT INTO t3 VALUES (1),(15),(27),(75),(117),(250);
ALTER TABLE t3 add skr int(10) not null;
select t1.gid, t2.sid, t3.uid from t2, t1, t3 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid;
select t1.gid, t2.sid, t3.uid from t3, t2, t1 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid;
# The following ORDER BY can be optimimized
EXPLAIN select t1.gid, t2.sid, t3.uid from t3, t2, t1 where t2.gid = t1.gid and t2.uid = t3.uid order by t1.gid, t3.uid;
EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.gid = t3.uid order by t1.gid,t3.skr;
# The following ORDER BY can't be optimimized
EXPLAIN SELECT t1.gid, t2.sid, t3.uid from t2, t1, t3 where t2.gid = t1.gid and t2.uid = t3.uid order by t3.uid, t1.gid;
EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.gid = t3.uid order by t3.skr,t1.gid;
EXPLAIN SELECT t1.gid, t3.uid from t1, t3 where t1.skr = t3.uid order by t1.gid,t3.skr;
drop table t1,t2,t3;