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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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8
mysql-test/main/partition_range.result
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@ -958,13 +958,17 @@ INSERT INTO t1 SELECT a + 10, b + 10 FROM t1;
INSERT INTO t1 SELECT a + 20, b + 20 FROM t1;
INSERT INTO t1 SELECT a + 40, b + 40 FROM t1;
INSERT INTO t2 SELECT * FROM t1;
ANALYZE TABLE t1,t2;
Table Op Msg_type Msg_text
test.t1 analyze status OK
test.t2 analyze status Table is already up to date
# plans should be identical
EXPLAIN SELECT a, MAX(b) FROM t1 WHERE a IN (10,100) GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 2 Using where; Using index
EXPLAIN SELECT a, MAX(b) FROM t2 WHERE a IN (10,100) GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range a a 5 NULL 2 Using where; Using index for group-by
1 SIMPLE t2 range a a 5 NULL 2 Using where; Using index
FLUSH status;
SELECT a, MAX(b) FROM t1 WHERE a IN (10, 100) GROUP BY a;
a MAX(b)
@ -980,5 +984,5 @@ a MAX(b)
# Should be no more than 4 reads.
SHOW status LIKE 'handler_read_key';
Variable_name Value
Handler_read_key 4
Handler_read_key 2
DROP TABLE t1, t2;