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drop table if exists t0, t1;
create table t0 (a int) engine=myisam;
insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
#
# Tests for single-table DELETE
#
explain select * from t0 where a=3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
explain delete from t0 where a=3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
# DELETE without WHERE is a special case:
explain delete from t0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL 8 Deleting all rows
create table t1 (a int, b int, filler char(100), key(a), key(b));
insert into t1
select A.a+10*B.a + 10*C.a, A.a+10*B.a + 10*C.a, 'filler'
from t0 A, t0 B, t0 C;
# This should use an index, possible_keys=NULL because there is no WHERE
explain delete from t1 order by a limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 5 NULL 2
# This should use range, possible_keys={a,b}
explain delete from t1 where a<20 and b < 10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a,b a 5 NULL 1 Using where
# This should use ALL + filesort
explain delete from t1 order by a+1 limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
# This should use range + using filesort
explain delete from t1 where a<20 order by b limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 1 Using where; Using filesort
# Try some subqueries:
explain delete from t1 where a < (select max(a) from t0);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 range a a 5 NULL 1 Using where
2 SUBQUERY t0 ALL NULL NULL NULL NULL 8
explain delete from t1 where a < (select max(a) from t0 where a < t1.b);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 512 Using where
2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 8 Using where
#
# Tests for multi-table DELETE
#
explain delete t1 from t0, t1 where t0.a = t1.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
1 SIMPLE t1 ref a a 5 test.t0.a 4
drop table t0, t1;
# ###################################################################
# ## EXPLAIN UPDATE tests
# ###################################################################
create table t0 (a int) engine=myisam;
insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
explain update t0 set a=3 where a=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
create table t1 (a int, b int, filler char(100), key(a), key(b));
insert into t1
select A.a+10*B.a + 10*C.a, A.a+10*B.a + 10*C.a, 'filler'
from t0 A, t0 B, t0 C;
explain update t1 set a=a+1 where 3>4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
explain update t1 set a=a+1 where a=3 and a=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
# This should use an index, possible_keys=NULL because there is no WHERE
explain update t1 set a=a+1 order by a limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
# This should use range, possible_keys={a,b}
explain update t1 set filler='fooo' where a<20 and b < 10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a,b a 5 NULL 1 Using where
# This should use ALL + filesort
explain update t1 set filler='fooo' order by a+1 limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
# This should use range + using filesort
explain update t1 set filler='fooo' where a<20 order by b limit 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 1 Using where; Using filesort
# Try some subqueries:
explain update t1 set filler='fooo' where a < (select max(a) from t0);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 range a a 5 NULL 1 Using where
2 SUBQUERY t0 ALL NULL NULL NULL NULL 8
explain update t1 set filler='fooo' where a < (select max(a) from t0 where a < t1.b);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 512 Using where
2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 8 Using where
#
# Tests for multi-table UPDATE
#
explain update t0, t1 set t1.a=t1.a+1 where t0.a = t1.a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
1 SIMPLE t1 ref a a 5 test.t0.a 4
drop table t0, t1;
#
# Try DELETE ... RETURNING ...
#
create table t0 (a int);
insert into t0 values (1),(2),(3),(4);
explain delete from t0 where a=1 returning a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 4 Using where
explain delete from t0 returning a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 4
drop table t0;
#
# MDEV-5070 - EXPLAIN INSERT ... SELECT crashes on 10.0-base-explain-slowquerylog
#
create table t0 (a int);
insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
create table t1 (a int);
explain insert into t1 select * from t0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 8
explain replace into t1 select * from t0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 8
drop table t0, t1;
#
# MDEV-5067: Valgrind warnings (Invalid read) in QPF_table_access::print_explain
#
CREATE TABLE t1 (i INT) ENGINE=MyISAM;
INSERT INTO t1 VALUES (7),(0),(9);
SELECT * FROM t1 INNER JOIN ( SELECT DISTINCT * FROM t1 ) AS sq ON (sq.i = t1.i);
i i
7 7
0 0
9 9
DROP TABLE t1;
#
# MDEV-5093, MDEV-5094: EXPLAIN PARTITIONS and EXPLAIN EXTENDED do not
# work for EXPLAIN UPDATE.
#
create table t1 (i int);
explain partitions update t1 set i = 3;
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
create table t2 (a int, b int) partition by hash(a) partitions 5;
insert into t2 values (0,0),(1,1),(2,2),(3,3),(4,4);
explain partitions update t2 set b=3 where a in (3,4);
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE t2 p3,p4 ALL NULL NULL NULL NULL 2 Using where
explain partitions delete from t2 where a in (3,4);
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE t2 p3,p4 ALL NULL NULL NULL NULL 2 Using where
explain extended update t2 set b=3 where a in (3,4);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 100.00 Using where
explain extended delete from t2 where a in (3,4);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 100.00 Using where
drop table t1,t2;
#
# Check the special case where partition pruning removed all partitions
#
create table t1 (a int, b int)
partition by range (a) (
partition p0 values less than (10),
partition p1 values less than (20),
partition p2 values less than (30)
);
insert into t1 values (9,9), (19,19), (29,29);
explain partitions select * from t1 where a in (32,33);
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
explain partitions delete from t1 where a in (32,33);
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No matching rows after partition pruning
explain partitions update t1 set b=12345 where a in (32,33);
id select_type table partitions type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No matching rows after partition pruning
drop table t1;
#
# Tests for EXPLAIN INSERT ... VALUES
#
create table t1 (a int, key(a));
explain insert into t1 values (1),(2),(3);
id select_type table type possible_keys key key_len ref rows Extra
1 INSERT t1 ALL NULL NULL NULL NULL NULL NULL
insert into t1 values (1),(2),(3);
create table t2 (a int, b int);
explain insert into t2 values
(10, 1+(select max(a) from t1)),
(11, 1+(select max(a+1) from t1));
id select_type table type possible_keys key key_len ref rows Extra
1 INSERT t2 ALL NULL NULL NULL NULL NULL NULL
3 SUBQUERY t1 index NULL a 5 NULL 3 Using index
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
drop table t1,t2;
#
# MDEV-5122: "Commands out of sync", "Malformed packet" or client hang up on unique key violation
#
drop table if exists t1;
Warnings:
Note 1051 Unknown table 'test.t1'
drop function if exists f1;
create table t1 (a int, unique(a));
create function f1(x int)
returns int
begin
insert into t1 values(x),(x);
return 10;
end|
select f1(100);
ERROR 23000: Duplicate entry '100' for key 'a'
select 'OK';
OK
OK
drop function f1;
drop table t1;
#
# MDEV-7038: Assertion `status_var.memory_used == 0' failed in THD::~THD()
# on disconnect after executing EXPLAIN for multi-table UPDATE
#
CREATE TABLE t1 (a INT);
CREATE VIEW v1 AS SELECT * FROM t1;
INSERT INTO t1 VALUES (1),(2);
EXPLAIN UPDATE v1, mysql.user SET v1.a = v1.a + 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE global_priv index NULL PRIMARY 1149 NULL 5 Using index
DROP TABLE t1;
DROP VIEW v1;
#
# MDEV-8299: MyISAM or Aria table gets corrupted after EXPLAIN INSERT and INSERT
#
CREATE TABLE t1 (pk INT NOT NULL AUTO_INCREMENT PRIMARY KEY, i INT, KEY(i)) ENGINE=MyISAM;
INSERT INTO t1 (i) VALUES (100),(200);
CREATE TABLE t2 (j INT) ENGINE=MyISAM;
INSERT INTO t2 VALUES (10),(20);
EXPLAIN INSERT INTO t1 (i) SELECT j FROM t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 2
INSERT INTO t1 (i) VALUES (300);
CHECK TABLE t1;
Table Op Msg_type Msg_text
test.t1 check status OK
DROP TABLE t1, t2;
#
# MDEV-8321: Assertion `! is_set()' failed in Diagnostics_area::set_eof_status on EXPLAIN INSERT ... UNION
#
CREATE TABLE t1 (a INT);
CREATE TABLE t2 (b INT);
CREATE TABLE t3 (c INT);
INSERT INTO t1 VALUES (1),(2);
INSERT INTO t2 VALUES (3),(4);
INSERT INTO t3 VALUES (5),(6);
EXPLAIN INSERT INTO t1 SELECT * FROM t2 UNION SELECT * FROM t3;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2
2 UNION t3 ALL NULL NULL NULL NULL 2
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
drop table t1,t2,t3;
#
# MDEV-6223: Assertion `! is_set()' fails in Diagnostics_area::set_eof_status on EXPLAIN INSERT executed as a PS
#
CREATE TABLE t1 (a INT) ENGINE = MyISAM;
CREATE TABLE t2 (b INT) ENGINE = MyISAM;
INSERT INTO t2 VALUES (1),(2);
PREPARE stmt FROM 'EXPLAIN INSERT INTO t1 SELECT * FROM t2';
EXECUTE stmt;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 2
drop table t1,t2;
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