mirror of
https://github.com/MariaDB/server.git
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658128af43
This patch contains a full implementation of the optimization
that allows to use in-memory rowid / primary filters built for range
conditions over indexes. In many cases usage of such filters reduce
the number of disk seeks spent for fetching table rows.
In this implementation the choice of what possible filter to be applied
(if any) is made purely on cost-based considerations.
This implementation re-achitectured the partial implementation of
the feature pushed by Galina Shalygina in the commit
8d5a11122c.
Besides this patch contains a better implementation of the generic
handler function handler::multi_range_read_info_const() that
takes into account gaps between ranges when calculating the cost of
range index scans. It also contains some corrections of the
implementation of the handler function records_in_range() for MyISAM.
This patch supports the feature for InnoDB and MyISAM.
415 lines
20 KiB
Text
415 lines
20 KiB
Text
drop table if exists t1;
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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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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 0 Const row not found
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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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id str
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1 NULL
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2 NULL
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select * from t1 where str="foo";
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id str
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3 foo
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explain select * from t1 where str is null;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref str str 11 const 2 Using index condition
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explain select * from t1 where str="foo";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 const str str 11 const 1
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explain select * from t1 ignore key (str) where str="foo";
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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 4 Using where
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explain select * from t1 use key (str,str) where str="foo";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 const str str 11 const 1
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explain select * from t1 use key (str,str,foo) where str="foo";
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ERROR 42000: Key 'foo' doesn't exist in table 't1'
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explain select * from t1 ignore key (str,str,foo) where str="foo";
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ERROR 42000: Key 'foo' doesn't exist in table 't1'
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drop table t1;
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explain select 1;
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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 No tables used
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create table t1 (a int not null);
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explain select count(*) from t1;
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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 Select tables optimized away
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insert into t1 values(1);
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explain select count(*) from t1;
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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 Select tables optimized away
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insert into t1 values(1);
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explain select count(*) from t1;
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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 Select tables optimized away
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drop table t1;
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set names koi8r;
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create table <20><><EFBFBD> (<28><><EFBFBD>0 int, <20><><EFBFBD>1 int, key <20><><EFBFBD>0 (<28><><EFBFBD>0), key <20><><EFBFBD>01 (<28><><EFBFBD>0,<2C><><EFBFBD>1));
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insert into <20><><EFBFBD> (<28><><EFBFBD>0) values (1);
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insert into <20><><EFBFBD> (<28><><EFBFBD>0) values (2);
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explain select <20><><EFBFBD>0 from <20><><EFBFBD> where <20><><EFBFBD>0=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE <09><><EFBFBD> ref <09><><EFBFBD>0,<2C><><EFBFBD>01 <09><><EFBFBD>0 5 const 1 Using index
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drop table <20><><EFBFBD>;
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set names latin1;
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select 3 into @v1;
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explain select 3 into @v1;
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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 No tables used
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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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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select 1 AS `f1`,1 AS `f2` from dual where 1
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explain extended select * from t1 where 0;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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Warnings:
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Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 0
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explain extended select * from t1 where 1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select 1 AS `f1`,1 AS `f2` from dual where 1
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explain extended select * from t1 having 0;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
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Warnings:
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Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` having 0
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explain extended select * from t1 having 1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select 1 AS `f1`,1 AS `f2` from dual having 1
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drop view v1;
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drop table t1;
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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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Warnings:
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Note 1831 Duplicate index `b_2`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_3`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_4`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_5`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_6`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_7`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_8`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_9`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_10`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_11`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_12`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_13`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_14`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_15`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_16`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_17`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_18`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_19`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_20`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_21`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_22`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_23`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_24`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_25`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_26`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_27`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_28`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_29`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_30`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_31`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_32`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_33`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_34`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_35`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_36`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_37`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_38`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_39`. This is deprecated and will be disallowed in a future release
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Note 1831 Duplicate index `b_40`. This is deprecated and will be disallowed in a future release
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INSERT INTO t2 VALUES (),(),();
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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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id select_type table type possible_keys key key_len ref rows Extra
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X X X X X X X X X
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X X X X X X X X X
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X X X X X X X X X Range checked for each record (index map: 0xFFFFFFFFFF)
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DROP TABLE t2;
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DROP TABLE t1;
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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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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer (flat, BNL join)
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Warnings:
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Note 1003 /* select#1 */ select 1 AS `1` from (/* select#2 */ select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `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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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer (flat, BNL join)
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Warnings:
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Note 1003 /* select#1 */ select 1 AS `1` from (/* select#2 */ select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `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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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer (flat, BNL join)
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Warnings:
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Note 1003 /* select#1 */ select 1 AS `1` from (/* select#2 */ select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `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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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer (flat, BNL join)
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Warnings:
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Note 1003 /* select#1 */ select 1 AS `1` from (/* select#2 */ select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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execute s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer (flat, BNL join)
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Warnings:
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Note 1003 /* select#1 */ select 1 AS `1` from (/* select#2 */ select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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DROP TABLE t1,t2;
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CREATE TABLE t1 (a INT PRIMARY KEY);
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EXPLAIN EXTENDED SELECT COUNT(a) FROM t1 USE KEY(a);
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ERROR 42000: Key 'a' doesn't exist in table 't1'
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DROP TABLE t1;
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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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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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ERROR 42S22: Unknown column 'd1.a' in 'where clause'
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DROP TABLE t1;
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#
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# Bug#48295:
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# explain extended crash with subquery and ONLY_FULL_GROUP_BY sql_mode
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#
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CREATE TABLE t1 (f1 INT not null);
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SELECT @@session.sql_mode INTO @old_sql_mode;
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SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
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EXPLAIN EXTENDED SELECT 1 FROM t1
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WHERE f1 > ALL( SELECT t.f1 FROM t1,t1 AS t );
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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2 SUBQUERY t1 system NULL NULL NULL NULL 0 0.00 Const row not found
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2 SUBQUERY t system NULL NULL NULL NULL 0 0.00 Const row not found
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Warnings:
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Note 1003 /* select#1 */ select 1 AS `1` from `test`.`t1` where 0
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SET SESSION sql_mode=@old_sql_mode;
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DROP TABLE t1;
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End of 5.0 tests.
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#
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# Bug#37870: Usage of uninitialized value caused failed assertion.
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#
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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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SET @save_join_cache_level=@@join_cache_level;
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SET join_cache_level=0;
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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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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY OUTR ALL NULL NULL NULL NULL 2 Using where
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1 PRIMARY INNR ALL NULL NULL NULL NULL 2 Using where; FirstMatch(OUTR)
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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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dt
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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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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY OUTR ALL NULL NULL NULL NULL 2 Using where
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1 PRIMARY INNR ALL NULL NULL NULL NULL 2 Using where; FirstMatch(OUTR)
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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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dt
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2001-01-01 01:01:01
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2001-01-01 01:01:01
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SET join_cache_level=@save_join_cache_level;
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drop tables t1, t2;
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#
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# Bug#47669: Query showed by EXPLAIN EXTENDED gives different result from original query
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#
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CREATE TABLE t1 (c int);
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INSERT INTO t1 VALUES (NULL);
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CREATE TABLE t2 (d int);
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INSERT INTO t2 VALUES (NULL), (0);
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EXPLAIN EXTENDED SELECT (SELECT 1 FROM t2 WHERE d = c) FROM t1;
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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 system NULL NULL NULL NULL 1 100.00
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2 SUBQUERY t2 ALL NULL NULL NULL NULL 2 100.00 Using where
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Warnings:
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Note 1276 Field or reference 'test.t1.c' of SELECT #2 was resolved in SELECT #1
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Note 1003 /* select#1 */ select (/* select#2 */ select 1 from `test`.`t2` where `test`.`t2`.`d` = NULL) AS `(SELECT 1 FROM t2 WHERE d = c)` from dual
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DROP TABLE t1, t2;
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#
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# Bug#30302: Tables that were optimized away are printed in the
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# EXPLAIN EXTENDED warning.
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#
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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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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select 1 AS `f1` from dual where 1
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explain extended select * from t1 join t2 on f1=f2 where f1=1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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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 select 1 AS `f1`,`test`.`t2`.`f2` AS `f2` from `test`.`t2` where `test`.`t2`.`f2` = 1
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drop table t1,t2;
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#
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# Bug #48419: another explain crash..
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#
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CREATE TABLE t1 (a INT);
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CREATE TABLE t2 (b BLOB, KEY b(b(100)));
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INSERT INTO t2 VALUES ('1'), ('2'), ('3');
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FLUSH TABLES;
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EXPLAIN SELECT 1 FROM t1 WHERE a = (SELECT 1 FROM t1 t JOIN t2 WHERE b <= 1 AND t.a);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL no matching row in const table
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DROP TABLE t1, t2;
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#
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# Bug #48573: difference of index selection between rpm binary and
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# .tar.gz, windows vs linux..
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#
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CREATE TABLE t1(c1 INT, c2 INT, c4 INT, c5 INT, KEY(c2, c5), KEY(c2, c4, c5));
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INSERT INTO t1 VALUES(4, 1, 1, 1);
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INSERT INTO t1 VALUES(3, 1, 1, 1);
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INSERT INTO t1 VALUES(2, 1, 1, 1);
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INSERT INTO t1 VALUES(1, 1, 1, 1);
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INSERT INTO t1 VALUES(5, 2, 1, 1);
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INSERT INTO t1 VALUES(6, 2, 1, 1);
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INSERT INTO t1 VALUES(7, 3, 1, 1);
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INSERT INTO t1 VALUES(9, 3, 1, 1);
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INSERT INTO t1 VALUES(10, 4, 1, 1);
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INSERT INTO t1 VALUES(11, 4, 1, 1);
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EXPLAIN SELECT c1 FROM t1 WHERE c2 = 1 AND c4 = 1 AND c5 = 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 ref c2,c2_2 c2 10 const,const 4 Using where
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DROP TABLE t1;
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#
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# Bug#56814 Explain + subselect + fulltext crashes server
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#
|
||
CREATE TABLE t1(f1 VARCHAR(6) NOT NULL,
|
||
FULLTEXT KEY(f1),UNIQUE(f1));
|
||
INSERT INTO t1 VALUES ('test');
|
||
EXPLAIN SELECT 1 FROM t1
|
||
WHERE 1 > ALL((SELECT t1.f1 FROM t1 JOIN t1 a ON (MATCH(t1.f1) AGAINST (""))
|
||
WHERE t1.f1 GROUP BY t1.f1));
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 PRIMARY t1 system NULL NULL NULL NULL 1
|
||
2 SUBQUERY a system NULL NULL NULL NULL 1
|
||
2 SUBQUERY t1 fulltext f1_2,f1 f1 0 1 Using where
|
||
PREPARE stmt FROM
|
||
'EXPLAIN SELECT 1 FROM t1
|
||
WHERE 1 > ALL((SELECT t1.f1 FROM t1 RIGHT OUTER JOIN t1 a
|
||
ON (MATCH(t1.f1) AGAINST (""))
|
||
WHERE t1.f1 GROUP BY t1.f1))';
|
||
EXECUTE stmt;
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 PRIMARY t1 system NULL NULL NULL NULL 1
|
||
2 SUBQUERY a system NULL NULL NULL NULL 1
|
||
2 SUBQUERY t1 fulltext f1_2,f1 f1 0 1 Using where
|
||
EXECUTE stmt;
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 PRIMARY t1 system NULL NULL NULL NULL 1
|
||
2 SUBQUERY a system NULL NULL NULL NULL 1
|
||
2 SUBQUERY t1 fulltext f1_2,f1 f1 0 1 Using where
|
||
DEALLOCATE PREPARE stmt;
|
||
PREPARE stmt FROM
|
||
'EXPLAIN SELECT 1 FROM t1
|
||
WHERE 1 > ALL((SELECT t1.f1 FROM t1 JOIN t1 a
|
||
ON (MATCH(t1.f1) AGAINST (""))
|
||
WHERE t1.f1 GROUP BY t1.f1))';
|
||
EXECUTE stmt;
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 PRIMARY t1 system NULL NULL NULL NULL 1
|
||
2 SUBQUERY a system NULL NULL NULL NULL 1
|
||
2 SUBQUERY t1 fulltext f1_2,f1 f1 0 1 Using where
|
||
EXECUTE stmt;
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 PRIMARY t1 system NULL NULL NULL NULL 1
|
||
2 SUBQUERY a system NULL NULL NULL NULL 1
|
||
2 SUBQUERY t1 fulltext f1_2,f1 f1 0 1 Using where
|
||
DEALLOCATE PREPARE stmt;
|
||
DROP TABLE t1;
|
||
End of 5.1 tests.
|
||
#
|
||
# Bug#11829785 EXPLAIN EXTENDED CRASH WITH RIGHT OUTER JOIN, SUBQUERIES
|
||
#
|
||
CREATE TABLE t1(a INT);
|
||
INSERT INTO t1 VALUES (0), (0);
|
||
PREPARE s FROM
|
||
'EXPLAIN EXTENDED
|
||
SELECT SUBSTRING(1, (SELECT 1 FROM t1 a1 RIGHT OUTER JOIN t1 ON 0)) AS d
|
||
FROM t1 WHERE 0 > ANY (SELECT @a FROM t1)';
|
||
EXECUTE s;
|
||
ERROR 21000: Subquery returns more than 1 row
|
||
DEALLOCATE PREPARE s;
|
||
DROP TABLE t1;
|
||
#
|
||
# Bug#776295: EXPLAIN EXTENDED with always false multiple equality
|
||
# in the WHERE condition of a derived table
|
||
#
|
||
CREATE TABLE t1 (a int) ;
|
||
CREATE TABLE t2 (a int) ;
|
||
INSERT INTO t2 VALUES (8);
|
||
set @tmp_optimizer_switch=@@optimizer_switch;
|
||
set optimizer_switch='derived_merge=off,derived_with_keys=off';
|
||
EXPLAIN EXTENDED
|
||
SELECT * FROM ( SELECT t1.a FROM t1,t2 WHERE t2.a = t1.a ) AS t;
|
||
id select_type table type possible_keys key key_len ref rows filtered Extra
|
||
1 PRIMARY <derived2> system NULL NULL NULL NULL 0 0.00 Const row not found
|
||
2 DERIVED NULL NULL NULL NULL NULL NULL NULL NULL no matching row in const table
|
||
Warnings:
|
||
Note 1003 /* select#1 */ select NULL AS `a` from (/* select#2 */ select NULL AS `a` from `test`.`t1` where 0) `t`
|
||
set optimizer_switch=@tmp_optimizer_switch;
|
||
DROP TABLE t1,t2;
|
||
#
|
||
# MDEV-7215: EXPLAIN REPLACE produces an error:
|
||
# Column count doesn't match value count
|
||
#
|
||
create table t1 (a int);
|
||
insert into t1 values (1);
|
||
create table t2 (b int, c int);
|
||
replace into t2 select 100, (select a from t1);
|
||
explain replace into t2 select 100, (select a from t1);
|
||
id select_type table type possible_keys key key_len ref rows Extra
|
||
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
||
2 SUBQUERY t1 system NULL NULL NULL NULL 1
|
||
drop table t1, t2;
|
||
# End of 10.1 tests
|