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f0ba35c617
This is a followup to vasil.dimov@oracle.com-20100816142329-yimenbuktd416z1a which improved the sampling algorithm.
188 lines
3.3 KiB
Plaintext
188 lines
3.3 KiB
Plaintext
SET SESSION STORAGE_ENGINE = InnoDB;
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drop table if exists t1, t2, t3,t4;
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create table t1 (
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pk1 int not NULL,
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key1 int(11),
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key2 int(11),
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PRIMARY KEY (pk1),
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KEY key1 (key1),
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KEY key2 (key2)
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);
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insert into t1 values (-5, 1, 1),
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(-100, 1, 1),
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(3, 1, 1),
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(0, 1, 1),
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(10, 1, 1);
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explain select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
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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_merge key1,key2 key1,key2 5,5 NULL 5 Using sort_union(key1,key2); Using where
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select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
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pk1 key1 key2
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-100 1 1
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-5 1 1
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0 1 1
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3 1 1
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10 1 1
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drop table t1;
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create table t1 (
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pk1 int unsigned not NULL,
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key1 int(11),
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key2 int(11),
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PRIMARY KEY (pk1),
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KEY key1 (key1),
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KEY key2 (key2)
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);
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insert into t1 values (0, 1, 1),
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(0xFFFFFFFF, 1, 1),
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(0xFFFFFFFE, 1, 1),
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(1, 1, 1),
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(2, 1, 1);
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select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
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pk1 key1 key2
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0 1 1
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1 1 1
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2 1 1
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4294967294 1 1
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4294967295 1 1
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drop table t1;
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create table t1 (
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pk1 char(4) not NULL,
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key1 int(11),
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key2 int(11),
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PRIMARY KEY (pk1),
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KEY key1 (key1),
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KEY key2 (key2)
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) collate latin2_general_ci;
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insert into t1 values ('a1', 1, 1),
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('b2', 1, 1),
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('A3', 1, 1),
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('B4', 1, 1);
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select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
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pk1 key1 key2
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a1 1 1
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A3 1 1
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b2 1 1
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B4 1 1
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drop table t1;
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create table t1 (
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pk1 int not NULL,
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pk2 char(4) not NULL collate latin1_german1_ci,
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pk3 char(4) not NULL collate latin1_bin,
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key1 int(11),
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key2 int(11),
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PRIMARY KEY (pk1,pk2,pk3),
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KEY key1 (key1),
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KEY key2 (key2)
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);
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insert into t1 values
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(1, 'u', 'u', 1, 1),
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(1, 'u', char(0xEC), 1, 1),
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(1, 'u', 'x', 1, 1);
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insert ignore into t1 select pk1, char(0xEC), pk3, key1, key2 from t1;
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insert ignore into t1 select pk1, 'x', pk3, key1, key2 from t1 where pk2='u';
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insert ignore into t1 select 2, pk2, pk3, key1, key2 from t1;
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select * from t1;
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pk1 pk2 pk3 key1 key2
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1 ì u 1 1
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1 ì x 1 1
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1 ì ì 1 1
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1 u u 1 1
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1 u x 1 1
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1 u ì 1 1
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1 x u 1 1
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1 x x 1 1
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1 x ì 1 1
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2 ì u 1 1
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2 ì x 1 1
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2 ì ì 1 1
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2 u u 1 1
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2 u x 1 1
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2 u ì 1 1
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2 x u 1 1
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2 x x 1 1
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2 x ì 1 1
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select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
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pk1 pk2 pk3 key1 key2
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1 ì u 1 1
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1 ì x 1 1
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1 ì ì 1 1
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1 u u 1 1
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1 u x 1 1
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1 u ì 1 1
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1 x u 1 1
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1 x x 1 1
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1 x ì 1 1
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2 ì u 1 1
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2 ì x 1 1
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2 ì ì 1 1
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2 u u 1 1
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2 u x 1 1
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2 u ì 1 1
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2 x u 1 1
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2 x x 1 1
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2 x ì 1 1
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alter table t1 drop primary key;
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select * from t1;
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pk1 pk2 pk3 key1 key2
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1 ì u 1 1
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1 ì x 1 1
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1 ì ì 1 1
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1 u u 1 1
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1 u x 1 1
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1 u ì 1 1
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1 x u 1 1
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1 x x 1 1
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1 x ì 1 1
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2 ì u 1 1
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2 ì x 1 1
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2 ì ì 1 1
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2 u u 1 1
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2 u x 1 1
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2 u ì 1 1
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2 x u 1 1
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2 x x 1 1
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2 x ì 1 1
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select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
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pk1 pk2 pk3 key1 key2
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1 ì u 1 1
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1 ì x 1 1
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1 ì ì 1 1
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1 u u 1 1
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1 u x 1 1
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1 u ì 1 1
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1 x u 1 1
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1 x x 1 1
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1 x ì 1 1
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2 ì u 1 1
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2 ì x 1 1
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2 ì ì 1 1
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2 u u 1 1
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2 u x 1 1
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2 u ì 1 1
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2 x u 1 1
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2 x x 1 1
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2 x ì 1 1
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drop table t1;
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create table t1 (
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pk1 varchar(8) NOT NULL default '',
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pk2 varchar(4) NOT NULL default '',
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key1 int(11),
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key2 int(11),
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primary key(pk1, pk2),
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KEY key1 (key1),
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KEY key2 (key2)
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);
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insert into t1 values ('','empt',2,2),
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('a','a--a',2,2),
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('bb','b--b',2,2),
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('ccc','c--c',2,2),
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('dddd','d--d',2,2);
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select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
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pk1 pk2 key1 key2
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empt 2 2
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a a--a 2 2
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bb b--b 2 2
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ccc c--c 2 2
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dddd d--d 2 2
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drop table t1;
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