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https://github.com/MariaDB/server.git
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75 lines
2.8 KiB
Text
75 lines
2.8 KiB
Text
drop table if exists t1;
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CREATE TABLE t1
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(a int auto_increment primary key,
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b char(20)
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);
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'#--------------------FN_DYNVARS_084_01-------------------------#'
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SELECT @@global.max_seeks_for_key = 10;
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@@global.max_seeks_for_key = 10
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0
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SELECT @@session.max_seeks_for_key = 10;
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@@session.max_seeks_for_key = 10
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0
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SET @@global.max_seeks_for_key = 20;
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SELECT @@global.max_seeks_for_key;
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@@global.max_seeks_for_key
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20
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INSERT into t1(b) values("AREc");
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explain select STRAIGHT_JOIN * from t1,t1 as t2 where 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 t1 system NULL NULL NULL NULL 1
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1 SIMPLE t2 system NULL NULL NULL NULL 1
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SET @@session.max_seeks_for_key = 2;
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SELECT @@session.max_seeks_for_key;
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@@session.max_seeks_for_key
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2
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INSERT into t1(b) values("BREc");
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INSERT into t1(b) values("CRec");
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explain select STRAIGHT_JOIN * from t1,t1 as t2 where 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 t1 ALL NULL NULL NULL NULL 3
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1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where; Using join buffer
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'#--------------------FN_DYNVARS_084_02-------------------------#'
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SELECT @@global.max_seeks_for_key = 10;
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@@global.max_seeks_for_key = 10
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0
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SELECT @@session.max_seeks_for_key = 10;
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@@session.max_seeks_for_key = 10
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0
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SET @@global.max_seeks_for_key = 20;
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SELECT @@global.max_seeks_for_key;
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@@global.max_seeks_for_key
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20
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INSERT into t1(b) values("AREc");
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explain select STRAIGHT_JOIN * from t1,t1 as t2 where 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 t1 ALL NULL NULL NULL NULL 4
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1 SIMPLE t2 ALL NULL NULL NULL NULL 4 Using where; Using join buffer
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SET @@session.max_seeks_for_key = 2;
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SELECT @@session.max_seeks_for_key;
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@@session.max_seeks_for_key
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2
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INSERT into t1(b) values("BREc");
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INSERT into t1(b) values("CRec");
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explain select STRAIGHT_JOIN * from t1,t1 as t2 where 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 t1 ALL NULL NULL NULL NULL 6
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1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join buffer
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INSERT INTO t1 values(null,"test");
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INSERT INTO t1 VALUES (null,"a"),(null,"a"),(null,"a"),
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(null,"a"),(null,"a"),(null,"a"),(null,"a"),
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(null,"a"),(null,"a"),(null,"a");
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explain SELECT STRAIGHT_JOIN * from t1,t1 as t2 where 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 t1 ALL NULL NULL NULL NULL 17
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1 SIMPLE t2 ALL NULL NULL NULL NULL 17 Using where; Using join buffer
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analyze table t1;
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Table Op Msg_type Msg_text
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test.t1 analyze status OK
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SET MAX_SEEKS_FOR_KEY=1;
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explain select STRAIGHT_JOIN * from t1,t1 as t2 where 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 t1 ALL NULL NULL NULL NULL 17
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1 SIMPLE t2 ALL NULL NULL NULL NULL 17 Using where; Using join buffer
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SET MAX_SEEKS_FOR_KEY=DEFAULT;
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drop table t1;
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