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82125f281f
checked for each record' The problem was in incorrectly calculated length of the buffer used to store a hexadecimal representation of an index map in select_describe(). This could result in buffer overrun and stack corruption under some circumstances. Fixed by correcting the calculation.
109 lines
4.6 KiB
Text
109 lines
4.6 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 1 Using where
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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 HY000: 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 HY000: 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 where; 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 Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` 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 Extra
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1 SIMPLE 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 Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` 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 Extra
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1 SIMPLE 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 Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` 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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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 const row not found
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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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