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Note: Setting to 10.5+ as the test case below only fails with rowid_filter=on (default in 10.5+, the switch is absent in previous versions), but possibly the test case can be further modified to make it irrelevant.
--source include/have_innodb.inc
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CREATE TABLE t1 (f int) ENGINE=InnoDB;
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INSERT INTO t1 VALUES (0),(4);
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CREATE TABLE t2 (pk int, a int, b varchar(10), PRIMARY KEY (pk), KEY a (a), KEY b (b)) ENGINE=InnoDB;
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INSERT INTO t2 VALUES
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(1,2,'v'),(2,3,'p'),(3,4,'p'),(4,2,'y'),(5,7,'q'),
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(6,4,'a'),(7,1,'d'),(8,5,'a'),(9,5,'z'),(10,1,'t'),
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(11,1,'y'),(12,5,'o'),(13,4,'a'),(14,5,'s'),(15,5,'m');
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ANALYZE TABLE t1, t2 PERSISTENT FOR ALL;
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SET optimizer_switch='rowid_filter=on'; # Default
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SET optimizer_switch='index_merge_sort_intersection=off'; # Default
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SELECT * FROM t1 JOIN t2 ON t1.f = t2.a WHERE t2.b >= 'j' AND t2.a != 5;
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SET optimizer_switch='index_merge_sort_intersection=on';
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SELECT * FROM t1 JOIN t2 ON t1.f = t2.a WHERE t2.b >= 'j' AND t2.a != 5;
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DROP TABLE t1, t2;
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10.5 674842be
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SET optimizer_switch='index_merge_sort_intersection=off';
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SELECT * FROM t1 JOIN t2 ON t1.f = t2.a WHERE t2.b >= 'j' AND t2.a != 5;
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f pk a b
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4 3 4 p
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SET optimizer_switch='index_merge_sort_intersection=on';
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SELECT * FROM t1 JOIN t2 ON t1.f = t2.a WHERE t2.b >= 'j' AND t2.a != 5;
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f pk a b
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Plans:
SET optimizer_switch='index_merge_sort_intersection=off';
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EXPLAIN EXTENDED SELECT * FROM t1 JOIN t2 ON t1.f = t2.a WHERE t2.b >= 'j' AND t2.a != 5;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2 100.00 Using where
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1 SIMPLE t2 ALL a,b NULL NULL NULL 15 48.89 Using where; Using join buffer (flat, BNL join)
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Warnings:
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Note 1003 select `test`.`t1`.`f` AS `f`,`test`.`t2`.`pk` AS `pk`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`f` and `test`.`t2`.`b` >= 'j' and `test`.`t1`.`f` <> 5
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SET optimizer_switch='index_merge_sort_intersection=on';
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EXPLAIN EXTENDED SELECT * FROM t1 JOIN t2 ON t1.f = t2.a WHERE t2.b >= 'j' AND t2.a != 5;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2 100.00 Using where
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1 SIMPLE t2 index_merge|filter a,b a,b|b 5,13|13 NULL 5 (73%) 73.33 Using sort_intersect(a,b); Using where; Using join buffer (flat, BNL join); Using rowid filter
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Warnings:
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Note 1003 select `test`.`t1`.`f` AS `f`,`test`.`t2`.`pk` AS `pk`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`f` and `test`.`t2`.`b` >= 'j' and `test`.`t1`.`f` <> 5
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