mirror of
https://github.com/MariaDB/server.git
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997445bc8e
- "Using MRR" is no longer shown with range access. - Instead, both range and BKA accesses will show one of the following: = "Rowid-ordered scan" = "Key-ordered scan" = "Key-ordered Rowid-ordered scan" depending on whether DS-MRR implementation will do scan keys in order, rowids in order, or both. - The patch also introduces a way for other storage engines/MRR implementations to pass information to EXPLAIN output about the properties of employed MRR scans.
148 lines
6.2 KiB
Text
148 lines
6.2 KiB
Text
drop table if exists t0,t1,t2,t3;
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set @save_join_cache_level=@@join_cache_level;
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set join_cache_level=6;
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set @save_storage_engine=@@storage_engine;
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set storage_engine=innodb;
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create table t0(a int);
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insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
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create table t1(a char(8), b char(8), filler char(100), primary key(a));
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` char(8) NOT NULL DEFAULT '',
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`b` char(8) DEFAULT NULL,
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`filler` char(100) DEFAULT NULL,
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PRIMARY KEY (`a`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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insert into t1 select
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concat('a-', 1000 + A.a + B.a*10 + C.a*100, '=A'),
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concat('b-', 1000 + A.a + B.a*10 + C.a*100, '=B'),
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'filler'
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from t0 A, t0 B, t0 C;
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create table t2 (a char(8));
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insert into t2 values ('a-1010=A'), ('a-1030=A'), ('a-1020=A');
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This should use join buffer:
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explain select * from t1, t2 where t1.a=t2.a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
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1 SIMPLE t1 eq_ref PRIMARY PRIMARY 8 test.t2.a 1 Using join buffer (flat, BKA join); Key-ordered scan
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This output must be sorted by value of t1.a:
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select * from t1, t2 where t1.a=t2.a;
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a b filler a
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a-1010=A b-1010=B filler a-1010=A
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a-1020=A b-1020=B filler a-1020=A
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a-1030=A b-1030=B filler a-1030=A
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drop table t1, t2;
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create table t1(
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a char(8) character set utf8, b int, filler char(100),
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primary key(a,b)
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);
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insert into t1 select
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concat('a-', 1000 + A.a + B.a*10 + C.a*100, '=A'),
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1000 + A.a + B.a*10 + C.a*100,
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'filler'
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from t0 A, t0 B, t0 C;
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create table t2 (a char(8) character set utf8, b int);
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insert into t2 values ('a-1010=A', 1010), ('a-1030=A', 1030), ('a-1020=A', 1020);
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explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
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1 SIMPLE t1 eq_ref PRIMARY PRIMARY 28 test.t2.a,test.t2.b 1 Using join buffer (flat, BKA join); Key-ordered scan
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select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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a b filler a b
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a-1010=A 1010 filler a-1010=A 1010
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a-1020=A 1020 filler a-1020=A 1020
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a-1030=A 1030 filler a-1030=A 1030
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insert into t2 values ('a-1030=A', 1030), ('a-1020=A', 1020);
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explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 5 Using where
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1 SIMPLE t1 eq_ref PRIMARY PRIMARY 28 test.t2.a,test.t2.b 1 Using join buffer (flat, BKA join); Key-ordered scan
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select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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a b filler a b
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a-1010=A 1010 filler a-1010=A 1010
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a-1020=A 1020 filler a-1020=A 1020
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a-1020=A 1020 filler a-1020=A 1020
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a-1030=A 1030 filler a-1030=A 1030
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a-1030=A 1030 filler a-1030=A 1030
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drop table t1, t2;
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create table t1(
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a varchar(8) character set utf8, b int, filler char(100),
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primary key(a,b)
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);
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insert into t1 select
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concat('a-', 1000 + A.a + B.a*10 + C.a*100, '=A'),
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1000 + A.a + B.a*10 + C.a*100,
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'filler'
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from t0 A, t0 B, t0 C;
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create table t2 (a char(8) character set utf8, b int);
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insert into t2 values ('a-1010=A', 1010), ('a-1030=A', 1030), ('a-1020=A', 1020);
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explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
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1 SIMPLE t1 eq_ref PRIMARY PRIMARY 30 test.t2.a,test.t2.b 1 Using index condition(BKA); Using join buffer (flat, BKA join); Key-ordered scan
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select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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a b filler a b
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a-1010=A 1010 filler a-1010=A 1010
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a-1020=A 1020 filler a-1020=A 1020
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a-1030=A 1030 filler a-1030=A 1030
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explain select * from t1, t2 where t1.a=t2.a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
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1 SIMPLE t1 ref PRIMARY PRIMARY 26 test.t2.a 1 Using index condition(BKA); Using join buffer (flat, BKA join); Key-ordered scan
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select * from t1, t2 where t1.a=t2.a;
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a b filler a b
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a-1010=A 1010 filler a-1010=A 1010
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a-1020=A 1020 filler a-1020=A 1020
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a-1030=A 1030 filler a-1030=A 1030
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drop table t1, t2;
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create table t1 (a int, b int, c int, filler char(100), primary key(a,b,c));
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insert into t1 select A.a, B.a, C.a, 'filler' from t0 A, t0 B, t0 C;
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insert into t1 values (11, 11, 11, 'filler');
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insert into t1 values (11, 11, 12, 'filler');
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insert into t1 values (11, 11, 13, 'filler');
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insert into t1 values (11, 22, 1234, 'filler');
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insert into t1 values (11, 33, 124, 'filler');
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insert into t1 values (11, 33, 125, 'filler');
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create table t2 (a int, b int);
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insert into t2 values (11,33), (11,22), (11,11);
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explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
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1 SIMPLE t1 ref PRIMARY PRIMARY 8 test.t2.a,test.t2.b 1 Using join buffer (flat, BKA join); Key-ordered scan
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select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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a b c filler a b
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11 11 11 filler 11 11
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11 11 12 filler 11 11
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11 11 13 filler 11 11
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11 22 1234 filler 11 22
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11 33 124 filler 11 33
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11 33 125 filler 11 33
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set join_cache_level=0;
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select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
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a b c filler a b
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11 33 124 filler 11 33
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11 33 125 filler 11 33
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11 22 1234 filler 11 22
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11 11 11 filler 11 11
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11 11 12 filler 11 11
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11 11 13 filler 11 11
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set join_cache_level=6;
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explain select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
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1 SIMPLE t1 ref PRIMARY PRIMARY 4 test.t2.a 1 Using index condition(BKA); Using join buffer (flat, BKA join); Key-ordered scan
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select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
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a b c filler a b
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set optimizer_switch='index_condition_pushdown=off';
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explain select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
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1 SIMPLE t1 ref PRIMARY PRIMARY 4 test.t2.a 1 Using where; Using join buffer (flat, BKA join); Key-ordered scan
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select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
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a b c filler a b
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set optimizer_switch='index_condition_pushdown=on';
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drop table t1,t2;
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set @@join_cache_level= @save_join_cache_level;
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set storage_engine=@save_storage_engine;
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drop table t0;
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