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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.
34 lines
1,011 B
Text
34 lines
1,011 B
Text
SET SESSION optimizer_switch = 'firstmatch=off,index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,loosescan=on,materialization=on,semijoin=on';
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CREATE TABLE t0 (a INT);
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INSERT INTO t0 VALUES (0),(1),(2),(3),(4);
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CREATE TABLE t1 (a INT, b INT, KEY(a));
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INSERT INTO t1 SELECT a, a from t0;
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CREATE TABLE t2 (a INT, b INT, PRIMARY KEY(a));
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INSERT INTO t2 SELECT * FROM t1;
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UPDATE t1 SET a=3, b=11 WHERE a=4;
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UPDATE t2 SET b=11 WHERE a=3;
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--echo
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--echo # This result is wrong, but will be fixed by Bug#46556
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SELECT * FROM t0 WHERE t0.a IN
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(SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
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SET join_cache_level = 6;
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--echo
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--echo # This result is even more wrong ;-)
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SELECT * FROM t0 WHERE t0.a IN
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(SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
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SET SESSION optimizer_switch = 'semijoin=off';
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--echo
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--echo # This result is correct
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SELECT * FROM t0 WHERE t0.a IN
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(SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
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DROP TABLE t0, t1, t2;
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