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Bug #36259 (Optimizing with ORDER BY) and bug#45828 (Optimizer won't
use partial primary key if another index can prevent filesort The fix for bug #28404 causes the covering ordering indexes to be preferred unconditionally over non-covering and ref indexes. Fixed by comparing the cost of using a covering index to the cost of using a ref index even for covering ordering indexes. Added an assertion to clarify the condition the local variables should be in.
This commit is contained in:
Georgi Kodinov
parent
b12a166d64
commit
d9e82ba86c
4 changed files with 166 additions and 6 deletions
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@ -1498,9 +1498,9 @@ INSERT INTO t1 VALUES
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(4,1,3,'pk',NULL),(5,1,3,'c2',NULL),
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(2,1,4,'c_extra',NULL),(3,1,4,'c_extra',NULL);
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EXPLAIN SELECT * FROM t1 WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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EXPLAIN SELECT * FROM t1 FORCE INDEX (PRIMARY) WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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SELECT * FROM t1 WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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SELECT * FROM t1 FORCE INDEX (PRIMARY) WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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DROP TABLE t1;
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@ -1701,10 +1701,10 @@ INSERT INTO t1 VALUES
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(4,1,2,'c2',NULL),(5,1,2,'c1',NULL),(2,1,3,'c2',NULL),(3,1,3,'c2',NULL),
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(4,1,3,'pk',NULL),(5,1,3,'c2',NULL),
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(2,1,4,'c_extra',NULL),(3,1,4,'c_extra',NULL);
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EXPLAIN SELECT * FROM t1 WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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EXPLAIN SELECT * FROM t1 FORCE INDEX (PRIMARY) WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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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 vid PRIMARY 12 NULL 16 Using where
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SELECT * FROM t1 WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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1 SIMPLE t1 index NULL PRIMARY 12 NULL 16 Using where
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SELECT * FROM t1 FORCE INDEX (PRIMARY) WHERE tid = 1 AND vid = 3 ORDER BY idx DESC;
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vid tid idx name type
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3 1 4 c_extra NULL
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3 1 3 c2 NULL
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@ -2137,4 +2137,75 @@ GROUP BY t1.b;
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a b c d a b e a b
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1 1 1 0 1 1 2 1 1
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DROP TABLE t1, t2, t3;
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#
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# Bug #45828: Optimizer won't use partial primary key if another
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# index can prevent filesort
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#
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CREATE TABLE `t1` (
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c1 int NOT NULL,
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c2 int NOT NULL,
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c3 int NOT NULL,
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PRIMARY KEY (c1,c2),
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KEY (c3)
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) ENGINE=InnoDB;
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INSERT INTO t1 VALUES (5,2,1246276747);
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INSERT INTO t1 VALUES (2,1,1246281721);
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INSERT INTO t1 VALUES (7,3,1246281756);
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INSERT INTO t1 VALUES (4,2,1246282139);
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INSERT INTO t1 VALUES (3,1,1246282230);
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INSERT INTO t1 VALUES (1,0,1246282712);
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INSERT INTO t1 VALUES (8,3,1246282765);
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INSERT INTO t1 SELECT c1+10,c2+10,c3+10 FROM t1;
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INSERT INTO t1 SELECT c1+100,c2+100,c3+100 from t1;
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INSERT INTO t1 SELECT c1+1000,c2+1000,c3+1000 from t1;
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INSERT INTO t1 SELECT c1+10000,c2+10000,c3+10000 from t1;
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INSERT INTO t1 SELECT c1+100000,c2+100000,c3+100000 from t1;
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INSERT INTO t1 SELECT c1+1000000,c2+1000000,c3+1000000 from t1;
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SELECT * FROM t1 WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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c1 c2 c3
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EXPLAIN SELECT * FROM t1 WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref PRIMARY,c3 PRIMARY 4 const 1 Using where; Using filesort
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EXPLAIN SELECT * FROM t1 FORCE INDEX (PRIMARY) WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref PRIMARY PRIMARY 4 const 1 Using where; Using filesort
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CREATE TABLE t2 (
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c1 int NOT NULL,
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c2 int NOT NULL,
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c3 int NOT NULL,
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KEY (c1,c2),
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KEY (c3)
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) ENGINE=InnoDB;
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explain SELECT * FROM t2 WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ref c1,c3 c1 4 const 1 Using where; Using filesort
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DROP TABLE t1,t2;
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#
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# 36259: Optimizing with ORDER BY
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#
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CREATE TABLE t1 (
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a INT NOT NULL AUTO_INCREMENT,
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b INT NOT NULL,
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c INT NOT NULL,
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d VARCHAR(5),
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e INT NOT NULL,
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PRIMARY KEY (a), KEY i2 (b,c,d)
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) ENGINE=InnoDB;
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INSERT INTO t1 (b,c,d,e) VALUES (1,1,'a',1), (2,2,'b',2);
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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EXPLAIN SELECT * FROM t1 WHERE b=1 AND c=1 ORDER BY a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref i2 i2 8 const,const 1 Using where; Using filesort
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EXPLAIN SELECT * FROM t1 FORCE INDEX(i2) WHERE b=1 and c=1 ORDER BY a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref i2 i2 8 const,const 1 Using where; Using filesort
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EXPLAIN SELECT * FROM t1 FORCE INDEX(PRIMARY) WHERE b=1 AND c=1 ORDER BY a;
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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 NULL PRIMARY 4 NULL 128 Using where
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DROP TABLE t1;
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End of 5.1 tests
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@ -380,4 +380,85 @@ SELECT * FROM t1, t2, t3
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DROP TABLE t1, t2, t3;
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--echo #
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--echo # Bug #45828: Optimizer won't use partial primary key if another
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--echo # index can prevent filesort
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--echo #
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# Create the table
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CREATE TABLE `t1` (
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c1 int NOT NULL,
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c2 int NOT NULL,
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c3 int NOT NULL,
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PRIMARY KEY (c1,c2),
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KEY (c3)
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) ENGINE=InnoDB;
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# populate with data
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INSERT INTO t1 VALUES (5,2,1246276747);
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INSERT INTO t1 VALUES (2,1,1246281721);
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INSERT INTO t1 VALUES (7,3,1246281756);
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INSERT INTO t1 VALUES (4,2,1246282139);
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INSERT INTO t1 VALUES (3,1,1246282230);
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INSERT INTO t1 VALUES (1,0,1246282712);
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INSERT INTO t1 VALUES (8,3,1246282765);
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INSERT INTO t1 SELECT c1+10,c2+10,c3+10 FROM t1;
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INSERT INTO t1 SELECT c1+100,c2+100,c3+100 from t1;
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INSERT INTO t1 SELECT c1+1000,c2+1000,c3+1000 from t1;
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INSERT INTO t1 SELECT c1+10000,c2+10000,c3+10000 from t1;
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INSERT INTO t1 SELECT c1+100000,c2+100000,c3+100000 from t1;
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INSERT INTO t1 SELECT c1+1000000,c2+1000000,c3+1000000 from t1;
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# query and no rows will match the c1 condition, whereas all will match c3
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SELECT * FROM t1 WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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# SHOULD use the pk.
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# index on c3 will be used instead of primary key
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EXPLAIN SELECT * FROM t1 WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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# if we force the primary key, we can see the estimate is 1
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EXPLAIN SELECT * FROM t1 FORCE INDEX (PRIMARY) WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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CREATE TABLE t2 (
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c1 int NOT NULL,
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c2 int NOT NULL,
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c3 int NOT NULL,
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KEY (c1,c2),
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KEY (c3)
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) ENGINE=InnoDB;
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# SHOULD use the pk.
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# if we switch it from a primary key to a regular index, it works correctly as well
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explain SELECT * FROM t2 WHERE c1 = 99999999 AND c3 > 1 ORDER BY c3;
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DROP TABLE t1,t2;
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--echo #
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--echo # 36259: Optimizing with ORDER BY
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--echo #
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CREATE TABLE t1 (
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a INT NOT NULL AUTO_INCREMENT,
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b INT NOT NULL,
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c INT NOT NULL,
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d VARCHAR(5),
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e INT NOT NULL,
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PRIMARY KEY (a), KEY i2 (b,c,d)
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) ENGINE=InnoDB;
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INSERT INTO t1 (b,c,d,e) VALUES (1,1,'a',1), (2,2,'b',2);
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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INSERT INTO t1 (b,c,d,e) SELECT RAND()*10000, RAND()*10000, d, e FROM t1;
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EXPLAIN SELECT * FROM t1 WHERE b=1 AND c=1 ORDER BY a;
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EXPLAIN SELECT * FROM t1 FORCE INDEX(i2) WHERE b=1 and c=1 ORDER BY a;
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EXPLAIN SELECT * FROM t1 FORCE INDEX(PRIMARY) WHERE b=1 AND c=1 ORDER BY a;
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DROP TABLE t1;
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--echo End of 5.1 tests
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@ -13132,9 +13132,17 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
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for (nr=0; nr < table->s->keys ; nr++)
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{
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int direction;
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if (keys.is_set(nr) &&
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(direction= test_if_order_by_key(order, table, nr, &used_key_parts)))
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{
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/*
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At this point we are sure that ref_key is a non-ordering
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key (where "ordering key" is a key that will return rows
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in the order required by ORDER BY).
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*/
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DBUG_ASSERT (ref_key != (int) nr);
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bool is_covering= table->covering_keys.is_set(nr) ||
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(nr == table->s->primary_key &&
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table->file->primary_key_is_clustered());
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@ -13215,7 +13223,7 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
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*/
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index_scan_time= select_limit/rec_per_key *
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min(rec_per_key, table->file->scan_time());
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if (is_covering ||
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if ((ref_key < 0 && is_covering) ||
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(ref_key < 0 && (group || table->force_index)) ||
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index_scan_time < read_time)
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{
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