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96e092dc73
WL#2474 "Multi Range Read: Change the default MRR implementation to implement new MRR interface"
WL#2475 "Batched range read functions for MyISAM/InnoDb"
"Index condition pushdown for MyISAM/InnoDB"
Igor's fix from sp1r-igor@olga.mysql.com-20080330055902-07614:
There could be observed the following problems:
1. EXPLAIN did not mention pushdown conditions from on expressions in the
'extra' column. As a result if a query had no where conditions pushed
down to a table, but had on conditions pushed to this table the 'extra'
column in the EXPLAIN for the table missed 'using where'.
2. Conditions for ref access were not eliminated from on expressions
though such conditions were eliminated from the where condition.
93 lines
3.9 KiB
Text
93 lines
3.9 KiB
Text
drop table if exists t1;
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SET SQL_SAFE_UPDATES=1,SQL_SELECT_LIMIT=4, SQL_MAX_JOIN_SIZE=9;
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create table t1 (a int auto_increment primary key, b char(20));
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insert into t1 values(1,"test");
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SELECT SQL_BUFFER_RESULT * from t1;
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a b
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1 test
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update t1 set b="a" where a=1;
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delete from t1 where a=1;
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insert into t1 values(1,"test"),(2,"test2");
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SELECT SQL_BUFFER_RESULT * from t1;
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a b
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1 test
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2 test2
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update t1 set b="a" where a=1;
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select 1 from t1,t1 as t2,t1 as t3;
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1
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1
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1
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1
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1
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update t1 set b="a";
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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update t1 set b="a" where b="test";
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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delete from t1;
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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delete from t1 where b="test";
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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delete from t1 where a+0=1;
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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select 1 from t1,t1 as t2,t1 as t3,t1 as t4,t1 as t5;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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update t1 set b="a" limit 1;
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update t1 set b="a" where b="b" limit 2;
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delete from t1 where b="test" limit 1;
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delete from t1 where a+0=1 limit 2;
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alter table t1 add key b (b);
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SET MAX_JOIN_SIZE=2;
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SELECT @@MAX_JOIN_SIZE, @@SQL_BIG_SELECTS;
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@@MAX_JOIN_SIZE @@SQL_BIG_SELECTS
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2 0
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insert into t1 values (null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a");
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SELECT * from t1 order by a;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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SET SQL_BIG_SELECTS=1;
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SELECT * from t1 order by a;
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a b
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2 test2
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3 a
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4 a
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5 a
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SET MAX_JOIN_SIZE=2;
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SELECT * from t1;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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SET MAX_JOIN_SIZE=DEFAULT;
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SELECT * from t1;
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a b
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2 test2
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3 a
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4 a
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5 a
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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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insert into t1 values (null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(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 b NULL NULL NULL 21
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1 SIMPLE t2 ref b b 21 test.t1.b 6
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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 b NULL NULL NULL 21
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1 SIMPLE t2 ref b b 21 test.t1.b 6
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SET MAX_SEEKS_FOR_KEY=DEFAULT;
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drop table t1;
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create table t1 (a int);
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insert into t1 values (1),(2),(3),(4),(5);
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insert into t1 select * from t1;
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insert into t1 select * from t1;
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insert into t1 select * from t1;
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set local max_join_size=8;
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select * from (select * from t1) x;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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set local max_join_size=1;
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select * from (select a.a as aa, b.a as ba from t1 a, t1 b) x;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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set local max_join_size=1;
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select * from (select 1 union select 2 union select 3) x;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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drop table t1;
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SET SQL_SAFE_UPDATES=0,SQL_SELECT_LIMIT=DEFAULT, SQL_MAX_JOIN_SIZE=DEFAULT;
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