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14994d2148
EXPLAIN EXTENDED warning.
Query optimizer searches for the constant tables and optimizes them away. This
means that fields of such tables are substituted for their values and on later
phases they are treated as constants. After this constant tables are removed
from the query execution plan. Nevertheless constant tables were shown in
the EXPLAIN EXTENDED warning thus producing query that might be not an
equivalent of the original query.
Now the print_join function skips all tables that were optimized away from
printing to the EXPLAIN EXTENDED warning. If all tables were optimized away it
produces the 'FROM dual' clause.
182 lines
5.1 KiB
Text
182 lines
5.1 KiB
Text
#
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# Test of different EXPLAIN's
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--disable_warnings
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drop table if exists t1;
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--enable_warnings
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create table t1 (id int not null, str char(10), unique(str));
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explain select * from t1;
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insert into t1 values (1, null),(2, null),(3, "foo"),(4, "bar");
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select * from t1 where str is null;
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select * from t1 where str="foo";
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explain select * from t1 where str is null;
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explain select * from t1 where str="foo";
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explain select * from t1 ignore key (str) where str="foo";
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explain select * from t1 use key (str,str) where str="foo";
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#The following should give errors
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--error 1176
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explain select * from t1 use key (str,str,foo) where str="foo";
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--error 1176
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explain select * from t1 ignore key (str,str,foo) where str="foo";
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drop table t1;
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explain select 1;
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create table t1 (a int not null);
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explain select count(*) from t1;
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insert into t1 values(1);
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explain select count(*) from t1;
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insert into t1 values(1);
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explain select count(*) from t1;
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drop table t1;
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#
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# Bug #3403 Wrong encoding in EXPLAIN SELECT output
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#
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set names koi8r;
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create table ÔÁÂ (ËÏÌ0 int, ËÏÌ1 int, key ÉÎÄ0 (ËÏÌ0), key ÉÎÄ01 (ËÏÌ0,ËÏÌ1));
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insert into ÔÁÂ (ËÏÌ0) values (1);
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insert into ÔÁÂ (ËÏÌ0) values (2);
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explain select ËÏÌ0 from ÔÁÂ where ËÏÌ0=1;
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drop table ÔÁÂ;
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set names latin1;
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# End of 4.1 tests
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#
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# Bug#15463: EXPLAIN SELECT..INTO hangs the client (QB, command line)
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#
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select 3 into @v1;
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explain select 3 into @v1;
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#
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# Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were
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# optimized away.
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#
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create table t1(f1 int, f2 int);
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insert into t1 values (1,1);
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create view v1 as select * from t1 where f1=1;
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explain extended select * from v1 where f2=1;
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explain extended select * from t1 where 0;
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explain extended select * from t1 where 1;
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explain extended select * from t1 having 0;
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explain extended select * from t1 having 1;
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drop view v1;
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drop table t1;
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#
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# Bug #32241: memory corruption due to large index map in 'Range checked for
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# each record'
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#
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CREATE TABLE t1(c INT);
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INSERT INTO t1 VALUES (),();
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CREATE TABLE t2 (b INT,
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b));
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INSERT INTO t2 VALUES (),(),();
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# We only need to make sure that there is no buffer overrun and the index map
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# is displayed correctly
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--replace_column 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X
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EXPLAIN SELECT 1 FROM
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(SELECT 1 FROM t2,t1 WHERE b < c GROUP BY 1 LIMIT 1) AS d2;
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DROP TABLE t2;
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DROP TABLE t1;
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#
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# Bug #34773: query with explain extended and derived table / other table
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# crashes server
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#
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CREATE TABLE t1(a INT);
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CREATE TABLE t2(a INT);
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INSERT INTO t1 VALUES (1),(2);
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INSERT INTO t2 VALUES (1),(2);
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EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
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EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
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prepare s1 from
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'EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
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execute s1;
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prepare s1 from
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'EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
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execute s1;
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execute s1;
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DROP TABLE t1,t2;
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#
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# Bug #43354: Use key hint can crash server in explain extended query
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#
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CREATE TABLE t1 (a INT PRIMARY KEY);
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--error ER_KEY_DOES_NOT_EXITS
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EXPLAIN EXTENDED SELECT COUNT(a) FROM t1 USE KEY(a);
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DROP TABLE t1;
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#
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# Bug#45989 memory leak after explain encounters an error in the query
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#
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CREATE TABLE t1(a LONGTEXT);
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INSERT INTO t1 VALUES (repeat('a',@@global.max_allowed_packet));
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INSERT INTO t1 VALUES (repeat('b',@@global.max_allowed_packet));
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--error ER_BAD_FIELD_ERROR
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EXPLAIN SELECT DISTINCT 1 FROM t1,
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(SELECT DISTINCTROW a AS away FROM t1 GROUP BY a WITH ROLLUP) as d1
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WHERE t1.a = d1.a;
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DROP TABLE t1;
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# End of 5.0 tests.
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--echo #
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--echo # Bug#37870: Usage of uninitialized value caused failed assertion.
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--echo #
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create table t1 (dt datetime not null, t time not null);
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create table t2 (dt datetime not null);
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insert into t1 values ('2001-01-01 1:1:1', '1:1:1'),
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('2001-01-01 1:1:1', '1:1:1');
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insert into t2 values ('2001-01-01 1:1:1'), ('2001-01-01 1:1:1');
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flush tables;
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EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
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flush tables;
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SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
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flush tables;
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EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
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flush tables;
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SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
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drop tables t1, t2;
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--echo #
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--echo # Bug#30302: Tables that were optimized away are printed in the
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--echo # EXPLAIN EXTENDED warning.
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--echo #
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create table t1(f1 int);
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create table t2(f2 int);
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insert into t1 values(1);
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insert into t2 values(1),(2);
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explain extended select * from t1 where f1=1;
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explain extended select * from t1 join t2 on f1=f2 where f1=1;
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drop table t1,t2;
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--echo End of 5.1 tests.
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