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MDEV-16188 Use in-memory PK filters built from range index scans

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This patch contains a full implementation of the optimization
that allows to use in-memory rowid / primary filters built for range  
conditions over indexes. In many cases usage of such filters reduce  
the number of disk seeks spent for fetching table rows.

In this implementation the choice of what possible filter to be applied  
(if any) is made purely on cost-based considerations.

This implementation re-achitectured the partial implementation of
the feature pushed by Galina Shalygina in the commit
8d5a11122c.

Besides this patch contains a better implementation of the generic  
handler function handler::multi_range_read_info_const() that
takes into account gaps between ranges when calculating the cost of
range index scans. It also contains some corrections of the
implementation of the handler function records_in_range() for MyISAM.

This patch supports the feature for InnoDB and MyISAM.
This commit is contained in:
Igor Babaev
2019-02-03 14:56:12 -08:00
parent 5f46670bd0
commit 658128af43
190 changed files with 5685 additions and 2017 deletions
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10
mysql-test/main/explain.result
View File

@ -13,7 +13,7 @@ id str
3 foo
explain select * from t1 where str is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref str str 11 const 1 Using index condition
1 SIMPLE t1 ref str str 11 const 2 Using index condition
explain select * from t1 where str="foo";
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const str str 11 const 1
@ -311,9 +311,15 @@ INSERT INTO t1 VALUES(4, 1, 1, 1);
INSERT INTO t1 VALUES(3, 1, 1, 1);
INSERT INTO t1 VALUES(2, 1, 1, 1);
INSERT INTO t1 VALUES(1, 1, 1, 1);
INSERT INTO t1 VALUES(5, 2, 1, 1);
INSERT INTO t1 VALUES(6, 2, 1, 1);
INSERT INTO t1 VALUES(7, 3, 1, 1);
INSERT INTO t1 VALUES(9, 3, 1, 1);
INSERT INTO t1 VALUES(10, 4, 1, 1);
INSERT INTO t1 VALUES(11, 4, 1, 1);
EXPLAIN SELECT c1 FROM t1 WHERE c2 = 1 AND c4 = 1 AND c5 = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref c2,c2_2 c2 10 const,const 3 Using where
1 SIMPLE t1 ref c2,c2_2 c2 10 const,const 4 Using where
DROP TABLE t1;
#
# Bug#56814 Explain + subselect + fulltext crashes server