Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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None
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None
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None
Description
The following query
SELECT * FROM t1 WHERE NOT EXISTS ( SELECT * FROM t2 WHERE b = a )
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on the test data returns 3 rows if executed with exists_to_in=on, materialization=off, and 2 rows otherwise. The correct result is 2 rows.
bzr version-info
revision-id: sanja@montyprogram.com-20120430093355-4yrpta86g97g6rhb
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date: 2012-04-30 12:33:55 +0300
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build-date: 2012-05-02 22:58:36 +0400
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revno: 3390
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optimizer_switch (default + exists_to_in=on + materialization=off):
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on,extended_keys=off,exists_to_in=on
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EXPLAIN with optimizer_switch = default + exists_to_in=on + materialization=off (wrong result):
id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 3 100.00 Using where
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Warnings:
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Note 1276 Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
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Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (not(((`test`.`t1`.`a` is not null) and <exists>(select `test`.`t2`.`b` from `test`.`t2` where ((`test`.`t2`.`b` is not null) and (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`b`))))))
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EXPLAIN with optimizer_switch = default + exists_to_in=off + materialization=off (correct result):
id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 3 100.00 Using where
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Warnings:
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Note 1276 Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
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Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (not(<expr_cache><`test`.`t1`.`a`>(exists(select 1 from `test`.`t2` where (`test`.`t2`.`b` = `test`.`t1`.`a`)))))
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Test case:
SET optimizer_switch='materialization=off';
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CREATE TABLE t1 ( a INT ) ;
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INSERT INTO t1 VALUES (0),(8),(1);
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CREATE TABLE t2 ( b INT ) ;
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INSERT INTO t2 VALUES (1),(2),(3);
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SELECT * FROM t1 WHERE NOT EXISTS ( SELECT * FROM t2 WHERE b = a );
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Expected result:
# a
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# ---
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# 0
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# 8
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Actual result:
# a
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# ---
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# 0
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# 8
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# 1
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Attachments
Issue Links
- relates to
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MDEV-38 NOT EXISTS to IN (part of exists2in transformation for 10.0)
- Closed