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4e9322e2ff
Raise notes if indexes cannot be used:
- in case of data type or collation mismatch (diferent error messages).
- in case if a table field was replaced to something else
(e.g. Item_func_conv_charset) during a condition rewrite.
Added option to write warnings and notes to the slow query log for
slow queries.
New variables added/changed:
- note_verbosity, with is a set of the following options:
basic - All old notes
unusable_keys - Print warnings about keys that cannot be used
for select, delete or update.
explain - Print unusable_keys warnings for EXPLAIN querys.
The default is 'basic,explain'. This means that for old installations
the only notable new behavior is that one will get notes about
unusable keys when one does an EXPLAIN for a query. One can turn all
of all notes by either setting note_verbosity to "" or setting sql_notes=0.
- log_slow_verbosity has a new option 'warnings'. If this is set
then warnings and notes generated are printed in the slow query log
(up to log_slow_max_warnings times per statement).
- log_slow_max_warnings - Max number of warnings written to
slow query log.
Other things:
- One can now use =ALL for any 'set' variable to set all options at once.
For example using "note_verbosity=ALL" in a config file or
"SET @@note_verbosity=ALL' in SQL.
- mysqldump will in the future use @@note_verbosity=""' instead of
@sql_notes=0 to disable notes.
- Added "enum class Data_type_compatibility" and changing the return type
of all Field::can_optimize*() methods from "bool" to this new data type.
Reviewer & Co-author: Alexander Barkov <bar@mariadb.com>
- The code that prints out the notes comes mainly from Alexander
124 lines
3.9 KiB
Text
124 lines
3.9 KiB
Text
drop table if exists t1;
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CREATE TABLE t1 (id CHAR(12) not null, PRIMARY KEY (id));
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insert into t1 values ('000000000001'),('000000000002');
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explain select * from t1 where id=000000000001;
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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 PRIMARY PRIMARY 12 NULL 2 Using where; Using index
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Warnings:
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Note 1105 Cannot use key `PRIMARY` part[0] for lookup: `test`.`t1`.`id` of type `char` = "1" of type `bigint`
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select * from t1 where id=000000000001;
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id
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000000000001
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delete from t1 where id=000000000002;
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select * from t1;
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id
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000000000001
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drop table t1;
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SELECT 'a' = 'a ';
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'a' = 'a '
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1
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SELECT 'a\0' < 'a';
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'a\0' < 'a'
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1
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SELECT 'a\0' < 'a ';
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'a\0' < 'a '
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1
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SELECT 'a\t' < 'a';
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'a\t' < 'a'
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1
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SELECT 'a\t' < 'a ';
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'a\t' < 'a '
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1
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CREATE TABLE t1 (a char(10) not null);
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INSERT INTO t1 VALUES ('a'),('a\0'),('a\t'),('a ');
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SELECT hex(a),STRCMP(a,'a'), STRCMP(a,'a ') FROM t1;
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hex(a) STRCMP(a,'a') STRCMP(a,'a ')
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61 0 0
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6100 -1 -1
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6109 -1 -1
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61 0 0
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DROP TABLE t1;
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SELECT CHAR(31) = '', '' = CHAR(31);
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CHAR(31) = '' '' = CHAR(31)
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0 0
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SELECT CHAR(30) = '', '' = CHAR(30);
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CHAR(30) = '' '' = CHAR(30)
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0 0
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create table t1 (a tinyint(1),b binary(1));
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insert into t1 values (0x01,0x01);
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select * from t1 where a=b;
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a b
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Warnings:
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Warning 1292 Truncated incorrect DECIMAL value: '\x01'
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select * from t1 where a=b and b=0x01;
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a b
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Warnings:
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Warning 1292 Truncated incorrect DECIMAL value: '\x01'
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drop table if exists t1;
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CREATE TABLE t1 (b int(2) zerofill, c int(2) zerofill);
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INSERT INTO t1 (b,c) VALUES (1,2), (1,1), (2,2);
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SELECT CONCAT(b,c), CONCAT(b,c) = '0101' FROM t1;
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CONCAT(b,c) CONCAT(b,c) = '0101'
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0102 0
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0101 1
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0202 0
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EXPLAIN EXTENDED SELECT b,c FROM t1 WHERE b = 1 AND CONCAT(b,c) = '0101';
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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 ALL NULL NULL NULL NULL 3 100.00 Using where
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Warnings:
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Note 1003 select `test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where `test`.`t1`.`b` = 1 and concat(`test`.`t1`.`b`,`test`.`t1`.`c`) = '0101'
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SELECT b,c FROM t1 WHERE b = 1 AND CONCAT(b,c) = '0101';
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b c
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01 01
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CREATE TABLE t2 (a int);
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INSERT INTO t2 VALUES (1),(2);
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SELECT a,
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(SELECT COUNT(*) FROM t1
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WHERE b = t2.a AND CONCAT(b,c) = CONCAT('0',t2.a,'01')) x
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FROM t2 ORDER BY a;
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a x
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1 1
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2 0
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EXPLAIN EXTENDED
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SELECT a,
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(SELECT COUNT(*) FROM t1
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WHERE b = t2.a AND CONCAT(b,c) = CONCAT('0',t2.a,'01')) x
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FROM t2 ORDER BY a;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00 Using filesort
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2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
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Warnings:
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Note 1276 Field or reference 'test.t2.a' of SELECT #2 was resolved in SELECT #1
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Note 1276 Field or reference 'test.t2.a' of SELECT #2 was resolved in SELECT #1
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Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,<expr_cache><`test`.`t2`.`a`>((/* select#2 */ select count(0) from `test`.`t1` where `test`.`t1`.`b` = `test`.`t2`.`a` and concat(`test`.`t1`.`b`,`test`.`t1`.`c`) = concat('0',`test`.`t2`.`a`,'01'))) AS `x` from `test`.`t2` order by `test`.`t2`.`a`
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DROP TABLE t1,t2;
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CREATE TABLE t1 (a TIMESTAMP);
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INSERT INTO t1 VALUES (NOW()),(NOW()),(NOW());
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SELECT * FROM t1 WHERE a > '2008-01-01' AND a = '0000-00-00';
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a
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DROP TABLE t1;
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End of 5.0 tests
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CREATE TABLE t1(a INT ZEROFILL);
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SELECT 1 FROM t1 WHERE t1.a IN (1, t1.a) AND t1.a=2;
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1
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DROP TABLE t1;
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CREATE TABLE t1 (a char(2), index (a));
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insert into t1 values ("aa"),("bb");
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select * from t1 where a="aa";
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a
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aa
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select * from t1 where a="aaa";
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a
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select * from t1 where a="aa ";
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a
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aa
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select * from t1 where a>="aaa";
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a
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bb
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explain select * from t1 where a="aaa";
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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 a a 3 const 1 Using where; Using index
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explain select * from t1 where a="aa ";
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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 a a 3 const 1 Using where; Using index
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drop table t1;
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