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Added thread variable max_seeks_for_key
Change optimizer to prefer key lookups before table scan Change table scans to be done after tables with constrains on scanned table mysql-test/r/distinct.result: Update results mysql-test/r/group_by.result: Update results mysql-test/r/heap.result: Update results mysql-test/r/join.result: Update results mysql-test/r/key_diff.result: Update results mysql-test/r/myisam.result: Update results mysql-test/r/order_by.result: Update results mysql-test/r/select_safe.result: Update results mysql-test/t/distinct.test: Change test to be repeatable mysql-test/t/join.test: Change test to be repeatable mysql-test/t/select_safe.test: Add tests for MAX_SEEKS_FOR_KEY sql/handler.h: Optimize structure for 64 bit machines (and to avoid problems with gdb) sql/item_cmpfunc.cc: Initialize not_null_tables_cache properly sql/mysqld.cc: Added max_seeks_for_key sql/set_var.cc: Added max_seeks_for_key sql/sql_class.h: Added max_seeks_for_key sql/sql_select.cc: Added max_seeks_for_key Change optimizer to prefer key lookups before table scan. Change table scans to be done after tables with constrains on scanned table
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@ -1,6 +1,6 @@
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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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create table t1 (a int auto_increment primary key, b char(20), key(b));
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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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@ -13,7 +13,7 @@ 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,t1 as t4;
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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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@ -22,11 +22,9 @@ select 1 from t1,t1 as t2,t1 as t3,t1 as t4;
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update t1 set b="a";
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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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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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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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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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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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@ -59,5 +57,22 @@ a b
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2 test2
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4 a
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5 a
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SELECT @@MAX_SEEKS_FOR_KEY;
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@@max_seeks_for_key
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4294967295
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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 * from t1,t1 as t2 where t1.b=t2.b;
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table type possible_keys key key_len ref rows Extra
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t1 ALL b NULL NULL NULL 21
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t2 ALL b NULL NULL NULL 16 Using where
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set MAX_SEEKS_FOR_KEY=1;
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explain select * from t1,t1 as t2 where t1.b=t2.b;
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table type possible_keys key key_len ref rows Extra
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t1 ALL b NULL NULL NULL 21
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t2 ref b b 21 t1.b 6 Using where
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SET MAX_SEEKS_FOR_KEY=DEFAULT;
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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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