mariadb/mysql-test/t/explain.test
Alexey Kopytov f3a8307397 Bug #48537: difference of index selection between rpm binary
and .tar.gz, windows vs linux..

On Intel x86 machines index selection by the MySQL query
optimizer could sometimes depend on the compiler version and
optimization flags used to build the server binary.

The problem was a result of a known issue with floating point
calculations on x86: since internal FPU precision (80 bit)
differs from precision used by programs (32-bit float or 64-bit
double), the result of calculating a complex expression may
depend on how FPU registers are allocated by the compiler and
whether intermediate values are spilled from FPU to memory. In
this particular case compiler versions and optimization flags
had an effect on cost calculation when choosing the best index
in best_access_path().

A possible solution to this problem which has already been
implemented in mysql-trunk is to limit FPU internal precision
to 64 bits. So the fix is a backport of the relevant code to
5.1 from mysql-trunk.

configure.in:
  Configure check for fpu_control.h
mysql-test/r/explain.result:
  Test case for bug #48537.
mysql-test/t/explain.test:
  Test case for bug #48537.
sql/mysqld.cc:
  Backport of the code to switch FPU on x86 to 64-bit precision.
2010-05-29 22:16:45 +04:00

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#
# Test of different EXPLAIN's
--disable_warnings
drop table if exists t1;
--enable_warnings
create table t1 (id int not null, str char(10), unique(str));
explain select * from t1;
insert into t1 values (1, null),(2, null),(3, "foo"),(4, "bar");
select * from t1 where str is null;
select * from t1 where str="foo";
explain select * from t1 where str is null;
explain select * from t1 where str="foo";
explain select * from t1 ignore key (str) where str="foo";
explain select * from t1 use key (str,str) where str="foo";
#The following should give errors
--error 1176
explain select * from t1 use key (str,str,foo) where str="foo";
--error 1176
explain select * from t1 ignore key (str,str,foo) where str="foo";
drop table t1;
explain select 1;
create table t1 (a int not null);
explain select count(*) from t1;
insert into t1 values(1);
explain select count(*) from t1;
insert into t1 values(1);
explain select count(*) from t1;
drop table t1;
#
# Bug #3403 Wrong encoding in EXPLAIN SELECT output
#
set names koi8r;
create table ÔÁÂ (ËÏÌ0 int, ËÏÌ1 int, key ÉÎÄ0 (ËÏÌ0), key ÉÎÄ01 (ËÏÌ0,ËÏÌ1));
insert into ÔÁÂ (ËÏÌ0) values (1);
insert into ÔÁÂ (ËÏÌ0) values (2);
explain select ËÏÌ0 from ÔÁÂ where ËÏÌ0=1;
drop table ÔÁÂ;
set names latin1;
# End of 4.1 tests
#
# Bug#15463: EXPLAIN SELECT..INTO hangs the client (QB, command line)
#
select 3 into @v1;
explain select 3 into @v1;
#
# Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were
# optimized away.
#
create table t1(f1 int, f2 int);
insert into t1 values (1,1);
create view v1 as select * from t1 where f1=1;
explain extended select * from v1 where f2=1;
explain extended select * from t1 where 0;
explain extended select * from t1 where 1;
explain extended select * from t1 having 0;
explain extended select * from t1 having 1;
drop view v1;
drop table t1;
#
# Bug #32241: memory corruption due to large index map in 'Range checked for
# each record'
#
CREATE TABLE t1(c INT);
INSERT INTO t1 VALUES (),();
CREATE TABLE t2 (b INT,
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
KEY(b),KEY(b),KEY(b),KEY(b),KEY(b));
INSERT INTO t2 VALUES (),(),();
# We only need to make sure that there is no buffer overrun and the index map
# is displayed correctly
--replace_column 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X
EXPLAIN SELECT 1 FROM
(SELECT 1 FROM t2,t1 WHERE b < c GROUP BY 1 LIMIT 1) AS d2;
DROP TABLE t2;
DROP TABLE t1;
#
# Bug #34773: query with explain extended and derived table / other table
# crashes server
#
CREATE TABLE t1(a INT);
CREATE TABLE t2(a INT);
INSERT INTO t1 VALUES (1),(2);
INSERT INTO t2 VALUES (1),(2);
EXPLAIN EXTENDED SELECT 1
FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
EXPLAIN EXTENDED SELECT 1
FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
prepare s1 from
'EXPLAIN EXTENDED SELECT 1
FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
execute s1;
prepare s1 from
'EXPLAIN EXTENDED SELECT 1
FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
execute s1;
execute s1;
DROP TABLE t1,t2;
#
# Bug #43354: Use key hint can crash server in explain extended query
#
CREATE TABLE t1 (a INT PRIMARY KEY);
--error ER_KEY_DOES_NOT_EXITS
EXPLAIN EXTENDED SELECT COUNT(a) FROM t1 USE KEY(a);
DROP TABLE t1;
#
# Bug#45989 memory leak after explain encounters an error in the query
#
CREATE TABLE t1(a LONGTEXT);
INSERT INTO t1 VALUES (repeat('a',@@global.max_allowed_packet));
INSERT INTO t1 VALUES (repeat('b',@@global.max_allowed_packet));
--error ER_BAD_FIELD_ERROR
EXPLAIN SELECT DISTINCT 1 FROM t1,
(SELECT DISTINCTROW a AS away FROM t1 GROUP BY a WITH ROLLUP) as d1
WHERE t1.a = d1.a;
DROP TABLE t1;
--echo #
--echo # Bug#48295:
--echo # explain extended crash with subquery and ONLY_FULL_GROUP_BY sql_mode
--echo #
CREATE TABLE t1 (f1 INT);
SELECT @@session.sql_mode INTO @old_sql_mode;
SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
# EXPLAIN EXTENDED (with subselect). used to crash. should give NOTICE.
--error ER_MIX_OF_GROUP_FUNC_AND_FIELDS
EXPLAIN EXTENDED SELECT 1 FROM t1
WHERE f1 > ALL( SELECT t.f1 FROM t1,t1 AS t );
SHOW WARNINGS;
SET SESSION sql_mode=@old_sql_mode;
DROP TABLE t1;
--echo End of 5.0 tests.
--echo #
--echo # Bug#37870: Usage of uninitialized value caused failed assertion.
--echo #
create table t1 (dt datetime not null, t time not null);
create table t2 (dt datetime not null);
insert into t1 values ('2001-01-01 1:1:1', '1:1:1'),
('2001-01-01 1:1:1', '1:1:1');
insert into t2 values ('2001-01-01 1:1:1'), ('2001-01-01 1:1:1');
flush tables;
EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
flush tables;
SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
flush tables;
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' );
flush tables;
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' );
drop tables t1, t2;
--echo #
--echo # Bug#47669: Query showed by EXPLAIN EXTENDED gives different result from original query
--echo #
CREATE TABLE t1 (c int);
INSERT INTO t1 VALUES (NULL);
CREATE TABLE t2 (d int);
INSERT INTO t2 VALUES (NULL), (0);
EXPLAIN EXTENDED SELECT (SELECT 1 FROM t2 WHERE d = c) FROM t1;
DROP TABLE t1, t2;
--echo #
--echo # Bug #48419: another explain crash..
--echo #
CREATE TABLE t1 (a INT);
CREATE TABLE t2 (b BLOB, KEY b(b(100)));
INSERT INTO t2 VALUES ('1'), ('2'), ('3');
FLUSH TABLES;
EXPLAIN SELECT 1 FROM t1 WHERE a = (SELECT 1 FROM t1 t JOIN t2 WHERE b <= 1 AND t.a);
DROP TABLE t1, t2;
--echo #
--echo # Bug #48573: difference of index selection between rpm binary and
--echo # .tar.gz, windows vs linux..
--echo #
CREATE TABLE t1(c1 INT, c2 INT, c4 INT, c5 INT, KEY(c2, c5), KEY(c2, c4, c5));
INSERT INTO t1 VALUES(4, 1, 1, 1);
INSERT INTO t1 VALUES(3, 1, 1, 1);
INSERT INTO t1 VALUES(2, 1, 1, 1);
INSERT INTO t1 VALUES(1, 1, 1, 1);
EXPLAIN SELECT c1 FROM t1 WHERE c2 = 1 AND c4 = 1 AND c5 = 1;
DROP TABLE t1;
--echo End of 5.1 tests.