database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-27 18:02:13 +03:00
Code Activity
Files
b66cdbd1eaeed7e96317a03a190c496fd062ec71
mariadb/mysql-test/main/key.result
Monty b66cdbd1ea Changing all cost calculation to be given in milliseconds 
This makes it easier to compare different costs and also allows
the optimizer to optimizer different storage engines more reliably.

- Added tests/check_costs.pl, a tool to verify optimizer cost calculations.
  - Most engine costs has been found with this program. All steps to
    calculate the new costs are documented in Docs/optimizer_costs.txt

- User optimizer_cost variables are given in microseconds (as individual
  costs can be very small). Internally they are stored in ms.
- Changed DISK_READ_COST (was DISK_SEEK_BASE_COST) from a hard disk cost
  (9 ms) to common SSD cost (400MB/sec).
- Removed cost calculations for hard disks (rotation etc).
- Changed the following handler functions to return IO_AND_CPU_COST.
  This makes it easy to apply different cost modifiers in ha_..time()
  functions for io and cpu costs.
  - scan_time()
  - rnd_pos_time() & rnd_pos_call_time()
  - keyread_time()
- Enhanched keyread_time() to calculate the full cost of reading of a set
  of keys with a given number of ranges and optional number of blocks that
  need to be accessed.
- Removed read_time() as keyread_time() + rnd_pos_time() can do the same
  thing and more.
- Tuned cost for: heap, myisam, Aria, InnoDB, archive and MyRocks.
  Used heap table costs for json_table. The rest are using default engine
  costs.
- Added the following new optimizer variables:
  - optimizer_disk_read_ratio
  - optimizer_disk_read_cost
  - optimizer_key_lookup_cost
  - optimizer_row_lookup_cost
  - optimizer_row_next_find_cost
  - optimizer_scan_cost
- Moved all engine specific cost to OPTIMIZER_COSTS structure.
- Changed costs to use 'records_out' instead of 'records_read' when
  recalculating costs.
- Split optimizer_costs.h to optimizer_costs.h and optimizer_defaults.h.
  This allows one to change costs without having to compile a lot of
  files.
- Updated costs for filter lookup.
- Use a better cost estimate in best_extension_by_limited_search()
  for the sorting cost.
- Fixed previous issues with 'filtered' explain column as we are now
  using 'records_out' (min rows seen for table) to calculate filtering.
  This greatly simplifies the filtering code in
  JOIN_TAB::save_explain_data().

This change caused a lot of queries to be optimized differently than
before, which exposed different issues in the optimizer that needs to
be fixed.  These fixes are in the following commits.  To not have to
change the same test case over and over again, the changes in the test
cases are done in a single commit after all the critical change sets
are done.

InnoDB changes:
- Updated InnoDB to not divide big range cost with 2.
- Added cost for InnoDB (innobase_update_optimizer_costs()).
- Don't mark clustered primary key with HA_KEYREAD_ONLY. This will
  prevent that the optimizer is trying to use index-only scans on
  the clustered key.
- Disabled ha_innobase::scan_time() and ha_innobase::read_time() and
  ha_innobase::rnd_pos_time() as the default engine cost functions now
  works good for InnoDB.

Other things:
- Added  --show-query-costs (\Q) option to mysql.cc to show the query
  cost after each query (good when working with query costs).
- Extended my_getopt with GET_ADJUSTED_VALUE which allows one to adjust
  the value that user is given. This is used to change cost from
  microseconds (user input) to milliseconds (what the server is
  internally using).
- Added include/my_tracker.h  ; Useful include file to quickly test
  costs of a function.
- Use handler::set_table() in all places instead of 'table= arg'.
- Added SHOW_OPTIMIZER_COSTS to sys variables. These are input and
  shown in microseconds for the user but stored as milliseconds.
  This is to make the numbers easier to read for the user (less
  pre-zeros).  Implemented in 'Sys_var_optimizer_cost' class.
- In test_quick_select() do not use index scans if 'no_keyread' is set
  for the table. This is what we do in other places of the server.
- Added THD parameter to Unique::get_use_cost() and
  check_index_intersect_extension() and similar functions to be able
  to provide costs to called functions.
- Changed 'records' to 'rows' in optimizer_trace.
- Write more information to optimizer_trace.
- Added INDEX_BLOCK_FILL_FACTOR_MUL (4) and INDEX_BLOCK_FILL_FACTOR_DIV (3)
  to calculate usage space of keys in b-trees. (Before we used numeric
  constants).
- Removed code that assumed that b-trees has similar costs as binary
  trees. Replaced with engine calls that returns the cost.
- Added Bitmap::find_first_bit()
- Added timings to join_cache for ANALYZE table (patch by Sergei Petrunia).
- Added records_init and records_after_filter to POSITION to remember
  more of what best_access_patch() calculates.
- table_after_join_selectivity() changed to recalculate 'records_out'
  based on the new fields from best_access_patch()

Bug fixes:
- Some queries did not update last_query_cost (was 0). Fixed by moving
  setting thd->...last_query_cost in JOIN::optimize().
- Write '0' as number of rows for const tables with a matching row.

Some internals:
- Engine cost are stored in OPTIMIZER_COSTS structure.  When a
  handlerton is created, we also created a new cost variable for the
  handlerton. We also create a new variable if the user changes a
  optimizer cost for a not yet loaded handlerton either with command
  line arguments or with SET
  @@global.engine.optimizer_cost_variable=xx.
- There are 3 global OPTIMIZER_COSTS variables:
  default_optimizer_costs   The default costs + changes from the
                            command line without an engine specifier.
  heap_optimizer_costs      Heap table costs, used for temporary tables
  tmp_table_optimizer_costs The cost for the default on disk internal
                            temporary table (MyISAM or Aria)
- The engine cost for a table is stored in table_share. To speed up
  accesses the handler has a pointer to this. The cost is copied
  to the table on first access. If one wants to change the cost one
  must first update the global engine cost and then do a FLUSH TABLES.
  This was done to be able to access the costs for an open table
  without any locks.
- When a handlerton is created, the cost are updated the following way:
  See sql/keycaches.cc for details:
  - Use 'default_optimizer_costs' as a base
  - Call hton->update_optimizer_costs() to override with the engines
    default costs.
  - Override the costs that the user has specified for the engine.
  - One handler open, copy the engine cost from handlerton to TABLE_SHARE.
  - Call handler::update_optimizer_costs() to allow the engine to update
    cost for this particular table.
  - There are two costs stored in THD. These are copied to the handler
    when the table is used in a query:
    - optimizer_where_cost
    - optimizer_scan_setup_cost
- Simply code in best_access_path() by storing all cost result in a
  structure. (Idea/Suggestion by Igor)
2023-02-02 23:54:45 +03:00

734 lines
25 KiB
Plaintext
Raw Blame History

SET SQL_WARNINGS=1;
CREATE TABLE t1 (
ID CHAR(32) NOT NULL,
name CHAR(32) NOT NULL,
value CHAR(255),
INDEX indexIDname (ID(8),name(8))
) ;
INSERT INTO t1 VALUES
('keyword','indexdir','/export/home/local/www/database/indexes/keyword');
INSERT INTO t1 VALUES ('keyword','urlprefix','text/ /text');
INSERT INTO t1 VALUES ('keyword','urlmap','/text/ /');
INSERT INTO t1 VALUES ('keyword','attr','personal employee company');
INSERT INTO t1 VALUES
('emailgids','indexdir','/export/home/local/www/database/indexes/emailgids');
INSERT INTO t1 VALUES ('emailgids','urlprefix','text/ /text');
INSERT INTO t1 VALUES ('emailgids','urlmap','/text/ /');
INSERT INTO t1 VALUES ('emailgids','attr','personal employee company');
SELECT value FROM t1 WHERE ID='emailgids' AND name='attr';
value
personal employee company
drop table t1;
CREATE TABLE t1 (
price int(5) DEFAULT '0' NOT NULL,
area varchar(40) DEFAULT '' NOT NULL,
type varchar(40) DEFAULT '' NOT NULL,
transityes enum('Y','N') DEFAULT 'Y' NOT NULL,
shopsyes enum('Y','N') DEFAULT 'Y' NOT NULL,
schoolsyes enum('Y','N') DEFAULT 'Y' NOT NULL,
petsyes enum('Y','N') DEFAULT 'Y' NOT NULL,
KEY price (price,area,type,transityes,shopsyes,schoolsyes,petsyes)
);
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','N','N','N','N');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','N','N','N','N');
INSERT IGNORE INTO t1 VALUES (900,'Vancouver','Shared/Roomate','','','','');
Warnings:
Warning 1265 Data truncated for column 'transityes' at row 1
Warning 1265 Data truncated for column 'shopsyes' at row 1
Warning 1265 Data truncated for column 'schoolsyes' at row 1
Warning 1265 Data truncated for column 'petsyes' at row 1
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
SELECT * FROM t1 WHERE area='Vancouver' and transityes='y' and schoolsyes='y' and ( ((type='1 Bedroom' or type='Studio/Bach') and (price<=500)) or ((type='2 Bedroom') and (price<=550)) or ((type='Shared/Roomate') and (price<=300)) or ((type='Room and Board') and (price<=500)) ) and price <= 400;
price area type transityes shopsyes schoolsyes petsyes
drop table t1;
CREATE TABLE t1 (program enum('signup','unique','sliding') not null, type enum('basic','sliding','signup'), sites set('mt'), PRIMARY KEY (program));
ALTER TABLE t1 modify program enum('signup','unique','sliding');
drop table t1;
CREATE TABLE t1 (
name varchar(50) DEFAULT '' NOT NULL,
author varchar(50) DEFAULT '' NOT NULL,
category decimal(10,0) DEFAULT '0' NOT NULL,
email varchar(50),
password varchar(50),
proxy varchar(50),
bitmap varchar(20),
msg varchar(255),
urlscol varchar(127),
urlhttp varchar(127),
timeout decimal(10,0),
nbcnx decimal(10,0),
creation decimal(10,0),
livinguntil decimal(10,0),
lang decimal(10,0),
type decimal(10,0),
subcat decimal(10,0),
subtype decimal(10,0),
reg char(1),
scs varchar(255),
capacity decimal(10,0),
userISP varchar(50),
CCident varchar(50) DEFAULT '' NOT NULL,
PRIMARY KEY (name,author,category)
);
INSERT INTO t1 VALUES
('patnom','patauteur',0,'p.favre@cryo-networks.fr',NULL,NULL,'#p2sndnq6ae5g1u6t','essai salut','scol://195.242.78.119:patauteur.patnom',NULL,NULL,NULL,950036174,-882087474,NULL,3,0,3,'1','Pub/patnom/futur_divers.scs',NULL,'pat','CC1');
INSERT INTO t1 VALUES
('LeNomDeMonSite','Marc',0,'m.barilley@cryo-networks.fr',NULL,NULL,NULL,NULL,'scol://195.242.78.119:Marc.LeNomDeMonSite',NULL,NULL,NULL,950560434,-881563214,NULL,3,0,3,'1','Pub/LeNomDeMonSite/domus_hibere.scs',NULL,'Marq','CC1');
select * from t1 where name='patnom' and author='patauteur' and category=0;
name author category email password proxy bitmap msg urlscol urlhttp timeout nbcnx creation livinguntil lang type subcat subtype reg scs capacity userISP CCident
patnom patauteur 0 p.favre@cryo-networks.fr NULL NULL #p2sndnq6ae5g1u6t essai salut scol://195.242.78.119:patauteur.patnom NULL NULL NULL 950036174 -882087474 NULL 3 0 3 1 Pub/patnom/futur_divers.scs NULL pat CC1
drop table t1;
create table t1
(
name_id int not null auto_increment,
name blob,
INDEX name_idx (name(5)),
primary key (name_id)
);
INSERT t1 VALUES(NULL,'/');
INSERT t1 VALUES(NULL,'[T,U]_axpby');
SELECT * FROM t1 WHERE name='[T,U]_axpy';
name_id name
SELECT * FROM t1 WHERE name='[T,U]_axpby';
name_id name
2 [T,U]_axpby
create table t2
(
name_id int not null auto_increment,
name char(255) binary,
INDEX name_idx (name(5)),
primary key (name_id)
);
INSERT t2 select * from t1;
SELECT * FROM t2 WHERE name='[T,U]_axpy';
name_id name
SELECT * FROM t2 WHERE name='[T,U]_axpby';
name_id name
2 [T,U]_axpby
CREATE TABLE t3 SELECT * FROM t2 WHERE name='[T,U]_axpby';
SELECT * FROM t2 WHERE name='[T,U]_axpby';
name_id name
2 [T,U]_axpby
drop table t1,t2,t3;
create table t1
(
SEQNO numeric(12 ) not null,
MOTYPEID numeric(12 ) not null,
MOINSTANCEID numeric(12 ) not null,
ATTRID numeric(12 ) not null,
VALUE varchar(120) not null,
primary key (SEQNO, MOTYPEID, MOINSTANCEID, ATTRID, VALUE )
);
INSERT INTO t1 VALUES (1, 1, 1, 1, 'a');
INSERT INTO t1 VALUES (1, 1, 1, 1, 'b');
INSERT INTO t1 VALUES (1, 1, 1, 1, 'a');
ERROR 23000: Duplicate entry '1-1-1-1-a' for key 'PRIMARY'
drop table t1;
CREATE TABLE t1 (
a tinytext NOT NULL,
b tinyint(3) unsigned NOT NULL default '0',
PRIMARY KEY (a(32),b)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('a',1),('a',2);
SELECT * FROM t1 WHERE a='a' AND b=2;
a b
a 2
SELECT * FROM t1 WHERE a='a' AND b in (2);
a b
a 2
SELECT * FROM t1 WHERE a='a' AND b in (1,2);
a b
a 1
a 2
drop table t1;
create table t1 (a int not null unique, b int unique, c int, d int not null primary key, key(c), e int not null unique);
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 PRIMARY 1 d A 0 NULL NULL BTREE NO
t1 0 a 1 a A 0 NULL NULL BTREE NO
t1 0 e 1 e A 0 NULL NULL BTREE NO
t1 0 b 1 b A NULL NULL NULL YES BTREE NO
t1 1 c 1 c A NULL NULL NULL YES BTREE NO
drop table t1;
CREATE TABLE t1 (c CHAR(10) NOT NULL,i INT NOT NULL AUTO_INCREMENT,
UNIQUE (c,i));
INSERT IGNORE INTO t1 (c) VALUES (NULL),(NULL);
Warnings:
Warning 1048 Column 'c' cannot be null
Warning 1048 Column 'c' cannot be null
SELECT * FROM t1;
c i
1
2
INSERT INTO t1 (c) VALUES ('a'),('a');
SELECT * FROM t1;
c i
1
2
a 1
a 2
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (c CHAR(10) NULL, i INT NOT NULL AUTO_INCREMENT,
UNIQUE (c,i));
INSERT INTO t1 (c) VALUES (NULL),(NULL);
SELECT * FROM t1;
c i
NULL 1
NULL 2
INSERT INTO t1 (c) VALUES ('a'),('a');
SELECT * FROM t1;
c i
NULL 1
NULL 2
a 1
a 2
drop table t1;
create table t1 (i int, a char(200), b text, unique (a), unique (b(300))) charset utf8;
insert ignore t1 values (1, repeat('a',210), repeat('b', 310));
Warnings:
Warning 1265 Data truncated for column 'a' at row 1
insert ignore t1 values (2, repeat(0xD0B1,215), repeat(0xD0B1, 310));
Warnings:
Warning 1265 Data truncated for column 'a' at row 1
select i, length(a), length(b), char_length(a), char_length(b) from t1;
i length(a) length(b) char_length(a) char_length(b)
1 200 310 200 310
2 400 620 200 310
select i from t1 where a=repeat(_utf8 'a',200);
i
1
select i from t1 where a=repeat(_utf8 0xD0B1,200);
i
2
select i from t1 where b=repeat(_utf8 'b',310);
i
1
drop table t1;
CREATE TABLE t1 (id int unsigned auto_increment, name char(50), primary key (id)) engine=myisam;
insert into t1 (name) values ('a'), ('b'),('c'),('d'),('e'),('f'),('g');
explain select 1 from t1 where id =2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 Using index
explain select 1 from t1 where id =2 or id=3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range PRIMARY PRIMARY 4 NULL 2 Using where; Using index
explain select name from t1 where id =2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
ALTER TABLE t1 DROP PRIMARY KEY, ADD INDEX (id);
explain select 1 from t1 where id =2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref id id 4 const 1 Using index
drop table t1;
CREATE TABLE t1 (numeropost mediumint(8) unsigned NOT NULL default '0', numreponse int(10) unsigned NOT NULL auto_increment, PRIMARY KEY (numeropost,numreponse), UNIQUE KEY numreponse (numreponse));
INSERT INTO t1 (numeropost,numreponse) VALUES ('1','1'),('1','2'),('2','3'),('2','4');
SELECT numeropost FROM t1 WHERE numreponse='1';
numeropost
1
EXPLAIN SELECT numeropost FROM t1 WHERE numreponse='1';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const numreponse numreponse 4 const 1
FLUSH TABLES;
SELECT numeropost FROM t1 WHERE numreponse='1';
numeropost
1
EXPLAIN SELECT numreponse+0 FROM t1 WHERE numreponse='1';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const numreponse numreponse 4 const 1 Using index
drop table t1;
create table t1 (c varchar(30) character set utf8, t text character set utf8, unique (c(2)), unique (t(3))) engine=myisam;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c` varchar(30) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci DEFAULT NULL,
`t` text CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci DEFAULT NULL,
UNIQUE KEY `c` (`c`(2)),
UNIQUE KEY `t` (`t`(3))
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
insert t1 values ('cccc', 'tttt'),
(0xD0B1212223D0B1D0B1D0B1D0B1D0B1, 0xD0B1D0B1212223D0B1D0B1D0B1D0B1),
(0xD0B1222123D0B1D0B1D0B1D0B1D0B1, 0xD0B1D0B1222123D0B1D0B1D0B1D0B1);
insert t1 (c) values ('cc22');
ERROR 23000: Duplicate entry 'cc' for key 'c'
insert t1 (t) values ('ttt22');
ERROR 23000: Duplicate entry 'ttt' for key 't'
insert t1 (c) values (0xD0B1212322D0B1D0B1D0B1D0B1D0B1);
ERROR 23000: Duplicate entry '\0431!' for key 'c'
insert t1 (t) values (0xD0B1D0B1212322D0B1D0B1D0B1D0B1);
ERROR 23000: Duplicate entry '\0431\0431!' for key 't'
select c from t1 where c='cccc';
c
cccc
select t from t1 where t='tttt';
t
tttt
select c from t1 where c=0xD0B1212223D0B1D0B1D0B1D0B1D0B1;
c
?!"#?????
select t from t1 where t=0xD0B1D0B1212223D0B1D0B1D0B1D0B1;
t
??!"#????
drop table t1;
DROP TABLE IF EXISTS t1;
Warnings:
Note 1051 Unknown table 'test.t1'
CREATE TABLE t1 (
c1 int,
c2 varbinary(240),
UNIQUE KEY (c1),
KEY (c2)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,'\Z\Z\Z\Z');
INSERT INTO t1 VALUES (2,'\Z\Z\Z\Z\Z\Z');
INSERT INTO t1 VALUES (3,'\Z\Z\Z\Z');
select c1 from t1 where c2='\Z\Z\Z\Z';
c1
1
3
DELETE FROM t1 WHERE (c1 = 1);
check table t1;
Table Op Msg_type Msg_text
test.t1 check status OK
select c1 from t1 where c2='\Z\Z\Z\Z';
c1
3
DELETE FROM t1 WHERE (c1 = 3);
check table t1;
Table Op Msg_type Msg_text
test.t1 check status OK
select c1 from t1 where c2='\Z\Z\Z\Z';
c1
truncate table t1;
insert into t1 values(1,"aaaa"),(2,"aaab"),(3,"aaac"),(4,"aaccc");
delete from t1 where c1=3;
delete from t1 where c1=1;
delete from t1 where c1=4;
check table t1;
Table Op Msg_type Msg_text
test.t1 check status OK
drop table t1;
create table t1 (c char(10), index (c(0)));
ERROR HY000: Key part 'c' length cannot be 0
create table t1 (c char(10), index (c,c));
ERROR 42S21: Duplicate column name 'c'
create table t1 (c1 char(10), c2 char(10), index (c1,c2,c1));
ERROR 42S21: Duplicate column name 'c1'
create table t1 (c1 char(10), c2 char(10), index (c1,c1,c2));
ERROR 42S21: Duplicate column name 'c1'
create table t1 (c1 char(10), c2 char(10), index (c2,c1,c1));
ERROR 42S21: Duplicate column name 'c1'
create table t1 (c1 char(10), c2 char(10));
alter table t1 add key (c1,c1);
ERROR 42S21: Duplicate column name 'c1'
alter table t1 add key (c2,c1,c1);
ERROR 42S21: Duplicate column name 'c1'
alter table t1 add key (c1,c2,c1);
ERROR 42S21: Duplicate column name 'c1'
alter table t1 add key (c1,c1,c2);
ERROR 42S21: Duplicate column name 'c1'
drop table t1;
create table t1 (
i1 INT NOT NULL,
i2 INT NOT NULL,
UNIQUE i1idx (i1),
UNIQUE i2idx (i2));
desc t1;
Field Type Null Key Default Extra
i1 int(11) NO PRI NULL
i2 int(11) NO UNI NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`i1` int(11) NOT NULL,
`i2` int(11) NOT NULL,
UNIQUE KEY `i1idx` (`i1`),
UNIQUE KEY `i2idx` (`i2`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
create table t1 (
c1 int,
c2 varchar(20) not null,
primary key (c1),
key (c2(10))
) engine=myisam;
insert into t1 values (1,'');
insert into t1 values (2,' \t\tTest String');
insert into t1 values (3,' \n\tTest String');
update t1 set c2 = 'New Test String' where c1 = 1;
select * from t1;
c1 c2
1 New Test String
2 Test String
3
Test String
drop table t1;
create table t1 (a varchar(10), b varchar(10), key(a(10),b(10)));
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` varchar(10) DEFAULT NULL,
`b` varchar(10) DEFAULT NULL,
KEY `a` (`a`,`b`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
alter table t1 modify b varchar(20);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` varchar(10) DEFAULT NULL,
`b` varchar(20) DEFAULT NULL,
KEY `a` (`a`,`b`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
alter table t1 modify a varchar(20);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` varchar(20) DEFAULT NULL,
`b` varchar(20) DEFAULT NULL,
KEY `a` (`a`,`b`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
create table t1 (a int not null primary key, b varchar(20) not null unique);
desc t1;
Field Type Null Key Default Extra
a int(11) NO PRI NULL
b varchar(20) NO UNI NULL
drop table t1;
create table t1 (a int not null primary key, b int not null unique);
desc t1;
Field Type Null Key Default Extra
a int(11) NO PRI NULL
b int(11) NO UNI NULL
drop table t1;
create table t1 (a int not null primary key, b varchar(20) not null, unique (b(10)));
desc t1;
Field Type Null Key Default Extra
a int(11) NO PRI NULL
b varchar(20) NO UNI NULL
drop table t1;
create table t1 (a int not null primary key, b varchar(20) not null, c varchar(20) not null, unique(b(10),c(10)));
desc t1;
Field Type Null Key Default Extra
a int(11) NO PRI NULL
b varchar(20) NO MUL NULL
c varchar(20) NO NULL
drop table t1;
create table t1 (
c1 int,
c2 char(12),
c3 varchar(123),
c4 timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
index (c1),
index i1 (c1),
index i2 (c2),
index i3 (c3),
unique i4 (c4),
index i5 (c1, c2, c3, c4),
primary key (c2, c3),
index (c2, c4));
Warnings:
Note 1831 Duplicate index `i1`. This is deprecated and will be disallowed in a future release
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c1` int(11) DEFAULT NULL,
`c2` char(12) NOT NULL,
`c3` varchar(123) NOT NULL,
`c4` timestamp NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
PRIMARY KEY (`c2`,`c3`),
UNIQUE KEY `i4` (`c4`),
KEY `c1` (`c1`),
KEY `i1` (`c1`),
KEY `i2` (`c2`),
KEY `i3` (`c3`),
KEY `i5` (`c1`,`c2`,`c3`,`c4`),
KEY `c2` (`c2`,`c4`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
alter table t1 drop index c1;
alter table t1 add index (c1);
Warnings:
Note 1831 Duplicate index `c1`. This is deprecated and will be disallowed in a future release
alter table t1 add index (c1);
Warnings:
Note 1831 Duplicate index `c1_2`. This is deprecated and will be disallowed in a future release
alter table t1 drop index i3;
alter table t1 add index i3 (c3);
alter table t1 drop index i2, drop index i4;
alter table t1 add index i2 (c2), add index i4 (c4);
alter table t1 drop index i2, drop index i4, add index i6 (c2, c4);
Warnings:
Note 1831 Duplicate index `i6`. This is deprecated and will be disallowed in a future release
alter table t1 add index i2 (c2), add index i4 (c4), drop index i6;
alter table t1 drop index i2, drop index i4, add unique i4 (c4);
alter table t1 add index i2 (c2), drop index i4, add index i4 (c4);
alter table t1 drop index c2, add index (c2(4),c3(7));
alter table t1 drop index c2, add index (c2(4),c3(7));
alter table t1 add primary key (c1, c2), drop primary key;
alter table t1 drop primary key;
alter table t1 add primary key (c1, c2), drop primary key;
ERROR 42000: Can't DROP INDEX `PRIMARY`; check that it exists
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c1` int(11) NOT NULL,
`c2` char(12) NOT NULL,
`c3` varchar(123) NOT NULL,
`c4` timestamp NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
KEY `i1` (`c1`),
KEY `i5` (`c1`,`c2`,`c3`,`c4`),
KEY `c1` (`c1`),
KEY `c1_2` (`c1`),
KEY `i3` (`c3`),
KEY `i2` (`c2`),
KEY `i4` (`c4`),
KEY `c2` (`c2`(4),`c3`(7))
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
insert into t1 values(1, 'a', 'a', NULL);
insert into t1 values(1, 'b', 'b', NULL);
alter table t1 drop index i3, drop index i2, drop index i1;
alter table t1 add index i3 (c3), add index i2 (c2), add unique index i1 (c1);
ERROR 23000: Duplicate entry '1' for key 'i1'
drop table t1;
CREATE TABLE t1( a TINYINT, KEY(a) ) ENGINE=MyISAM;
INSERT INTO t1 VALUES( 1 );
ALTER TABLE t1 DISABLE KEYS;
EXPLAIN SELECT MAX(a) FROM t1 FORCE INDEX(a);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1
drop table t1;
CREATE TABLE t1 (
a INTEGER auto_increment PRIMARY KEY,
b INTEGER NOT NULL,
c INTEGER NOT NULL,
d CHAR(64)
);
CREATE TABLE t2 (
a INTEGER auto_increment PRIMARY KEY,
b INTEGER NOT NULL,
c SMALLINT NOT NULL,
d DATETIME NOT NULL,
e SMALLINT NOT NULL,
f INTEGER NOT NULL,
g INTEGER NOT NULL,
h SMALLINT NOT NULL,
i INTEGER NOT NULL,
j INTEGER NOT NULL,
UNIQUE INDEX (b),
INDEX (b, d, e, f, g, h, i, j, c),
INDEX (c)
);
INSERT INTO t2 VALUES
(NULL, 1, 254, '1000-01-01 00:00:00', 257, 0, 0, 0, 0, 0),
(NULL, 2, 1, '2004-11-30 12:00:00', 1, 0, 0, 0, 0, 0),
(NULL, 3, 1, '2004-11-30 12:00:00', 1, 0, 0, 2, -21600, 0),
(NULL, 4, 1, '2004-11-30 12:00:00', 1, 0, 0, 2, -10800, 0),
(NULL, 5, 1, '2004-11-30 12:00:00', 1, 0, 0, 5, -10800, 0),
(NULL, 6, 1, '2004-11-30 12:00:00', 102, 0, 0, 0, 0, 0),
(NULL, 7, 1, '2004-11-30 12:00:00', 105, 2, 0, 0, 0, 0),
(NULL, 8, 1, '2004-11-30 12:00:00', 105, 10, 0, 0, 0, 0);
INSERT INTO t1 (b, c, d) VALUES
(3388000, -553000, NULL),
(3388000, -553000, NULL);
SELECT *
FROM t2 c JOIN t1 pa ON c.b = pa.a
WHERE c.c = 1
ORDER BY c.b, c.d
;
a b c d e f g h i j a b c d
2 2 1 2004-11-30 12:00:00 1 0 0 0 0 0 2 3388000 -553000 NULL
DROP TABLE t1, t2;
create table t1(a int not null, key aa(a),
b char(10) not null, unique key bb(b(1)),
c char(4) not null, unique key cc(c));
desc t1;
Field Type Null Key Default Extra
a int(11) NO MUL NULL
b char(10) NO UNI NULL
c char(4) NO PRI NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL,
`b` char(10) NOT NULL,
`c` char(4) NOT NULL,
UNIQUE KEY `cc` (`c`),
UNIQUE KEY `bb` (`b`(1)),
KEY `aa` (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
create table t1(a int not null, key aa(a),
b char(10) not null, unique key bb(b(1)),
c char(4) not null);
desc t1;
Field Type Null Key Default Extra
a int(11) NO MUL NULL
b char(10) NO UNI NULL
c char(4) NO NULL
alter table t1 add unique key cc(c);
desc t1;
Field Type Null Key Default Extra
a int(11) NO MUL NULL
b char(10) NO UNI NULL
c char(4) NO PRI NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL,
`b` char(10) NOT NULL,
`c` char(4) NOT NULL,
UNIQUE KEY `cc` (`c`),
UNIQUE KEY `bb` (`b`(1)),
KEY `aa` (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
End of 5.0 tests
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a INT PRIMARY KEY AUTO_INCREMENT);
INSERT INTO t1 VALUES (), (), ();
SELECT 1 AS c1
FROM t1
ORDER BY (
SELECT 1 AS c2
FROM t1
GROUP BY GREATEST(LAST_INSERT_ID(), t1.a) ASC
LIMIT 1);
c1
1
1
1
DROP TABLE t1;
CREATE TABLE t1 (a INT, b INT, INDEX (a,b));
INSERT INTO t1 (a, b)
VALUES
(1,1), (1,2), (1,3), (1,4), (1,5),
(2,2), (2,3), (2,1), (3,1), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6);
ANALYZE table t1;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE
(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY t1 range a a 5 NULL 2 Using where; Using index for group-by
SELECT 1 as RES FROM t1 AS t1_outer WHERE
(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
RES
DROP TABLE t1;
#
# Bug#18144: Cost with FORCE/USE index seems incorrect in some cases.
#
# We are interested in showing that the cost for the last plan is higher
# than for the preceding two plans.
#
CREATE TABLE t1( a INT, b INT, KEY( a ) );
INSERT INTO t1 values (1, 2), (1, 3), (2, 3), (2, 4), (3, 4), (3, 5);
EXPLAIN SELECT a, SUM( b ) FROM t1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using temporary; Using filesort
SHOW STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 0.014749
EXPLAIN SELECT a, SUM( b ) FROM t1 USE INDEX( a ) GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using temporary; Using filesort
SHOW STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 0.014749
EXPLAIN SELECT a, SUM( b ) FROM t1 FORCE INDEX( a ) GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 5 NULL 6
SHOW STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 0.014749
DROP TABLE t1;
#
# MDEV-21480: Unique key using ref access though eq_ref access can be used
#
create table t1(a int, b int,c int, primary key(a), unique key(b,c));
insert into t1 select seq, seq, seq from seq_1_to_10;
create table t2(a int, b int,c int);
insert into t2 select seq, seq, seq+1 from seq_1_to_100;
EXPLAIN SELECT t1.c, t2.c FROM t1, t2 WHERE t1.b=t2.a and t1.c=t2.b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE t1 eq_ref b b 10 test.t2.a,test.t2.b 1 Using index
SELECT t1.c, t2.c FROM t1, t2 WHERE t1.b=t2.a and t1.c=t2.b;
c c
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11
alter table t1 drop PRIMARY KEY;
alter table t1 add PRIMARY KEY(b,c);
EXPLAIN SELECT t1.c, t2.c FROM t1, t2 WHERE t1.b=t2.a and t1.c=t2.b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE t1 eq_ref PRIMARY,b PRIMARY 8 test.t2.a,test.t2.b 1 Using index
SELECT t1.c, t2.c FROM t1, t2 WHERE t1.b=t2.a and t1.c=t2.b;
c c
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11
drop table t1,t2;
#
# MDEV-13756 Implement descending index: KEY (a DESC, b ASC)
#
create table t1 (a int, b int, key(a), key(a desc));
drop table t1;
# Check some issues with FORCE INDEX and full index scans
# (Does FORCE INDEX force an index scan)
#
create table t1 (a int primary key, b int, c int, d int,
key k1 (b) using BTREE, key k2 (c,d) using btree) engine=heap;
insert into t1 select seq as a, seq as b, seq as c, seq as d
from seq_1_to_100;
explain select sum(a+b) from t1 force index (k1) where b>0 and a=99;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range k1 k1 5 NULL 100 Using where
explain select sum(a+b) from t1 force index (k1) where a>0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 Using where
explain select sum(a+b) from t1 force index (k1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100
explain select sum(a+b) from t1 force index for join (k1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100
explain select sum(a+b) from t1 force index for order by (k1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100
explain select sum(a+b) from t1 force index (k1,k2);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100
select sum(a+b) from t1 force index (k1);
sum(a+b)
10100
explain select sum(a+b) from t1 force index (primary);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100
select sum(a+b) from t1 force index (primary);
sum(a+b)
10100
explain select straight_join sum(a+b) from seq_1_to_10 as s, t1 force index (k2) where t1.a=s.seq;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE s index PRIMARY PRIMARY 8 NULL 10 Using index
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 Using where; Using join buffer (flat, BNL join)
drop table t1;
View Git Blame Copy Permalink