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aa713f5ae2
EXPLAIN EXTENDED should always print the field item used in the left part of an equality expression from the SET clause of an update statement as a reference to table column. Approved by Oleksandr Byelkin <sanja@mariadb.com>
329 lines
13 KiB
Text
329 lines
13 KiB
Text
drop table if exists t0, t1;
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create table t0 (a int) engine=myisam;
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insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
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#
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# Tests for single-table DELETE
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#
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explain select * from t0 where a=3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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explain delete from t0 where a=3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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# DELETE without WHERE is a special case:
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explain delete from t0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL 8 Deleting all rows
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create table t1 (a int, b int, filler char(100), key(a), key(b));
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insert into t1
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select A.a+10*B.a + 10*C.a, A.a+10*B.a + 10*C.a, 'filler'
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from t0 A, t0 B, t0 C;
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# This should use an index, possible_keys=NULL because there is no WHERE
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explain delete from t1 order by a limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL a 5 NULL 2
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# This should use range, possible_keys={a,b}
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explain delete from t1 where a<20 and b < 10;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a,b a 5 NULL 1 Using where
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# This should use ALL + filesort
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explain delete from t1 order by a+1 limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
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# This should use range + using filesort
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explain delete from t1 where a<20 order by b limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 1 Using where; Using filesort
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# Try some subqueries:
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explain delete from t1 where a < (select max(a) from t0);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 range a a 5 NULL 1 Using where
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2 SUBQUERY t0 ALL NULL NULL NULL NULL 8
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explain delete from t1 where a < (select max(a) from t0 where a < t1.b);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 512 Using where
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2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 8 Using where
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#
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# Tests for multi-table DELETE
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#
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explain delete t1 from t0, t1 where t0.a = t1.a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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1 SIMPLE t1 ref a a 5 test.t0.a 4
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drop table t0, t1;
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# ###################################################################
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# ## EXPLAIN UPDATE tests
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# ###################################################################
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create table t0 (a int) engine=myisam;
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insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
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explain update t0 set a=3 where a=4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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create table t1 (a int, b int, filler char(100), key(a), key(b));
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insert into t1
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select A.a+10*B.a + 10*C.a, A.a+10*B.a + 10*C.a, 'filler'
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from t0 A, t0 B, t0 C;
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explain update t1 set a=a+1 where 3>4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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explain update t1 set a=a+1 where a=3 and a=4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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# This should use an index, possible_keys=NULL because there is no WHERE
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explain update t1 set a=a+1 order by a limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
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# This should use range, possible_keys={a,b}
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explain update t1 set filler='fooo' where a<20 and b < 10;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a,b a 5 NULL 1 Using where
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# This should use ALL + filesort
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explain update t1 set filler='fooo' order by a+1 limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
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# This should use range + using filesort
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explain update t1 set filler='fooo' where a<20 order by b limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 1 Using where; Using filesort
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# Try some subqueries:
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explain update t1 set filler='fooo' where a < (select max(a) from t0);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 range a a 5 NULL 1 Using where
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2 SUBQUERY t0 ALL NULL NULL NULL NULL 8
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explain update t1 set filler='fooo' where a < (select max(a) from t0 where a < t1.b);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 512 Using where
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2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 8 Using where
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#
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# Tests for multi-table UPDATE
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#
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explain update t0, t1 set t1.a=t1.a+1 where t0.a = t1.a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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1 SIMPLE t1 ref a a 5 test.t0.a 4
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drop table t0, t1;
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#
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# Try DELETE ... RETURNING ...
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#
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create table t0 (a int);
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insert into t0 values (1),(2),(3),(4);
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explain delete from t0 where a=1 returning a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 4 Using where
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explain delete from t0 returning a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 4
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drop table t0;
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#
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# MDEV-5070 - EXPLAIN INSERT ... SELECT crashes on 10.0-base-explain-slowquerylog
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#
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create table t0 (a int);
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insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
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create table t1 (a int);
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explain insert into t1 select * from t0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8
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explain replace into t1 select * from t0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8
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drop table t0, t1;
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#
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# MDEV-5067: Valgrind warnings (Invalid read) in QPF_table_access::print_explain
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#
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CREATE TABLE t1 (i INT) ENGINE=MyISAM;
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INSERT INTO t1 VALUES (7),(0),(9);
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SELECT * FROM t1 INNER JOIN ( SELECT DISTINCT * FROM t1 ) AS sq ON (sq.i = t1.i);
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i i
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7 7
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0 0
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9 9
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DROP TABLE t1;
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#
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# MDEV-5093, MDEV-5094: EXPLAIN PARTITIONS and EXPLAIN EXTENDED do not
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# work for EXPLAIN UPDATE.
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#
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create table t1 (i int);
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explain partitions update t1 set i = 3;
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 0
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create table t2 (a int, b int) partition by hash(a) partitions 5;
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insert into t2 values (0,0),(1,1),(2,2),(3,3),(4,4);
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explain partitions update t2 set b=3 where a in (3,4);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 p3,p4 ALL NULL NULL NULL NULL 2 Using where
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explain partitions delete from t2 where a in (3,4);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 p3,p4 ALL NULL NULL NULL NULL 2 Using where
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explain extended update t2 set b=3 where a in (3,4);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2 100.00 Using where
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Warnings:
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Note 1003 update `test`.`t2` set `test`.`t2`.`b` = 3 where `test`.`t2`.`a` in (3,4)
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explain extended delete from t2 where a in (3,4);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2 100.00 Using where
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Warnings:
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Note 1003 delete from `test`.`t2` where `test`.`t2`.`a` in (3,4)
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drop table t1,t2;
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#
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# Check the special case where partition pruning removed all partitions
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#
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create table t1 (a int, b int)
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partition by range (a) (
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partition p0 values less than (10),
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partition p1 values less than (20),
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partition p2 values less than (30)
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);
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insert into t1 values (9,9), (19,19), (29,29);
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explain partitions select * from t1 where a in (32,33);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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explain partitions delete from t1 where a in (32,33);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No matching rows after partition pruning
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explain partitions update t1 set b=12345 where a in (32,33);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No matching rows after partition pruning
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drop table t1;
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#
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# Tests for EXPLAIN INSERT ... VALUES
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#
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create table t1 (a int, key(a));
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explain insert into t1 values (1),(2),(3);
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id select_type table type possible_keys key key_len ref rows Extra
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1 INSERT t1 ALL NULL NULL NULL NULL NULL NULL
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insert into t1 values (1),(2),(3);
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create table t2 (a int, b int);
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explain insert into t2 values
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(10, 1+(select max(a) from t1)),
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(11, 1+(select max(a+1) from t1));
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id select_type table type possible_keys key key_len ref rows Extra
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1 INSERT t2 ALL NULL NULL NULL NULL NULL NULL
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3 SUBQUERY t1 index NULL a 5 NULL 3 Using index
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2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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drop table t1,t2;
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#
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# MDEV-5122: "Commands out of sync", "Malformed packet" or client hang up on unique key violation
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#
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drop table if exists t1;
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Warnings:
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Note 1051 Unknown table 'test.t1'
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drop function if exists f1;
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create table t1 (a int, unique(a));
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create function f1(x int)
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returns int
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begin
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insert into t1 values(x),(x);
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return 10;
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end|
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select f1(100);
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ERROR 23000: Duplicate entry '100' for key 'a'
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select 'OK';
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OK
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OK
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drop function f1;
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drop table t1;
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#
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# MDEV-7038: Assertion `status_var.memory_used == 0' failed in THD::~THD()
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# on disconnect after executing EXPLAIN for multi-table UPDATE
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#
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CREATE TABLE t1 (a INT);
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CREATE VIEW v1 AS SELECT * FROM t1;
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INSERT INTO t1 VALUES (1),(2);
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EXPLAIN UPDATE v1, mysql.user SET v1.a = v1.a + 1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2
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1 SIMPLE global_priv index NULL PRIMARY 420 NULL 5 Using index
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DROP TABLE t1;
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DROP VIEW v1;
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#
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# MDEV-8299: MyISAM or Aria table gets corrupted after EXPLAIN INSERT and INSERT
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#
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CREATE TABLE t1 (pk INT NOT NULL AUTO_INCREMENT PRIMARY KEY, i INT, KEY(i)) ENGINE=MyISAM;
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INSERT INTO t1 (i) VALUES (100),(200);
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CREATE TABLE t2 (j INT) ENGINE=MyISAM;
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INSERT INTO t2 VALUES (10),(20);
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EXPLAIN INSERT INTO t1 (i) SELECT j FROM t2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2
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INSERT INTO t1 (i) VALUES (300);
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CHECK TABLE t1;
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Table Op Msg_type Msg_text
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test.t1 check status OK
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DROP TABLE t1, t2;
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#
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# MDEV-8321: Assertion `! is_set()' failed in Diagnostics_area::set_eof_status on EXPLAIN INSERT ... UNION
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#
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CREATE TABLE t1 (a INT);
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CREATE TABLE t2 (b INT);
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CREATE TABLE t3 (c INT);
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INSERT INTO t1 VALUES (1),(2);
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INSERT INTO t2 VALUES (3),(4);
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INSERT INTO t3 VALUES (5),(6);
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EXPLAIN INSERT INTO t1 SELECT * FROM t2 UNION SELECT * FROM t3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t2 ALL NULL NULL NULL NULL 2
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2 UNION t3 ALL NULL NULL NULL NULL 2
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NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
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drop table t1,t2,t3;
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#
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# MDEV-6223: Assertion `! is_set()' fails in Diagnostics_area::set_eof_status on EXPLAIN INSERT executed as a PS
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#
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CREATE TABLE t1 (a INT) ENGINE = MyISAM;
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CREATE TABLE t2 (b INT) ENGINE = MyISAM;
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INSERT INTO t2 VALUES (1),(2);
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PREPARE stmt FROM 'EXPLAIN INSERT INTO t1 SELECT * FROM t2';
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EXECUTE stmt;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2
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drop table t1,t2;
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#
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# MDEV-31181: EXPLAIN EXTENDED for single-table DELETE with IN predicand
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#
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create table t1 (a int);
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insert into t1 values (3), (7), (1), (3), (4);
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create table t2 (pk int primary key);
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insert into t2 values (3), (5), (1);
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create table t3 (a int, key(a));
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insert into t3 values (7), (5), (7), (3);
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explain extended delete from t1 where a in (select pk from t2);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 5 100.00 Using where
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2 DEPENDENT SUBQUERY t2 unique_subquery PRIMARY PRIMARY 4 func 1 100.00 Using index
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Warnings:
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Note 1003 /* select#1 */ delete from `test`.`t1` where <in_optimizer>(`test`.`t1`.`a`,<exists>(<primary_index_lookup>(<cache>(`test`.`t1`.`a`) in t2 on PRIMARY)))
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delete from t1 where a in (select pk from t2);
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select * from t1;
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a
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7
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4
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explain extended delete from t1 where a in (select a from t3);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00 Using where
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2 DEPENDENT SUBQUERY t3 index_subquery a a 5 func 2 100.00 Using index
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Warnings:
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Note 1003 /* select#1 */ delete from `test`.`t1` where <in_optimizer>(`test`.`t1`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t1`.`a`) in t3 on a)))
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delete from t1 where a in (select a from t3);
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select * from t1;
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a
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4
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drop table t1,t2,t3;
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#
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# MDEV-31224: EXPLAIN EXTENDED for multi-table update of system table
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#
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CREATE TABLE t1 (a INT);
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INSERT INTO t1 VALUES (1),(2);
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CREATE TABLE t2 (b INT) ENGINE=MyISAM;
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INSERT INTO t2 VALUES (3);
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EXPLAIN EXTENDED UPDATE t1, t2 SET b = 4 WHERE a IN (6,2);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t2 system NULL NULL NULL NULL 1 100.00
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2 100.00 Using where
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Warnings:
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Note 1003 update `test`.`t1` set `test`.`t2`.`b` = 4 where `test`.`t1`.`a` in (6,2)
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UPDATE t1, t2 SET b = 4 WHERE a IN (6,2);
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SELECT * from t2;
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b
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4
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DROP TABLE t1, t2;
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# End of 10.4 tests
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