database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

MDEV-28846 Poor performance when rowid filter contains no elements

Browse Source 
When a range rowid filter was used with an index ref access the cost of
accessing the index entries for the records rejected by the filter was not
taken into account. For a ref access by an index with big average number
of records per key this led to poor execution plans if selectivity of the
used filter was high.
The patch resolves this problem. It also introduces a minor optimization
that skips look-ups into a filter that turns out to be empty.
With this patch the output of ANALYZE stmt reports the number of look-ups
into used rowid filters.
The patch also back-ports from 10.5 the code that properly sets the field
TABLE::file::table for opened temporary tables.

The test cases that were supposed to use rowid filters have been adjusted
in order to use similar execution plans after this fix.

Approved by Oleksandr Byelkin <sanja@mariadb.com>
This commit is contained in:
Igor Babaev
2022-10-17 16:44:10 -07:00
parent f1bbc1cd19
commit 58cd0bd59e
21 changed files with 1797 additions and 170 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
mysql-test/main/select.result
View File

@ -3474,13 +3474,13 @@ INSERT INTO t2 VALUES
EXPLAIN
SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL c NULL NULL NULL 18 Using where
1 SIMPLE t1 eq_ref|filter PRIMARY,b PRIMARY|b 4|5 test.t2.c 1 (30%) Using where; Using rowid filter
1 SIMPLE t1 range PRIMARY,b b 5 NULL 3 Using index condition
1 SIMPLE t2 ref c c 5 test.t1.a 2
EXPLAIN
SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6 AND a > 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL c NULL NULL NULL 18 Using where
1 SIMPLE t1 eq_ref|filter PRIMARY,b PRIMARY|b 4|5 test.t2.c 1 (30%) Using where; Using rowid filter
1 SIMPLE t1 range PRIMARY,b b 5 NULL 3 Using index condition; Using where
1 SIMPLE t2 ref c c 5 test.t1.a 2
DROP TABLE t1, t2;
create table t1 (
a int unsigned not null auto_increment primary key,
@ -3616,7 +3616,7 @@ t3.a=t2.a AND t3.c IN ('bb','ee');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 range si si 5 NULL 4 Using index condition; Using where
1 SIMPLE t3 eq_ref|filter PRIMARY,ci PRIMARY|ci 4|5 test.t2.a 1 (30%) Using where; Using rowid filter
1 SIMPLE t3 eq_ref PRIMARY,ci PRIMARY 4 test.t2.a 1 Using where
EXPLAIN
SELECT t3.a FROM t1,t2,t3
WHERE t1.id = 8 AND t2.i BETWEEN t1.b AND t1.e AND
@ -3624,7 +3624,7 @@ t3.a=t2.a AND t3.c IN ('bb','ee') ;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 range si,ai si 5 NULL 4 Using index condition; Using where
1 SIMPLE t3 eq_ref|filter PRIMARY,ci PRIMARY|ci 4|5 test.t2.a 1 (30%) Using where; Using rowid filter
1 SIMPLE t3 eq_ref PRIMARY,ci PRIMARY 4 test.t2.a 1 Using where
EXPLAIN
SELECT t3.a FROM t1,t2 FORCE INDEX (si),t3
WHERE t1.id = 8 AND (t2.i=t1.b OR t2.i=t1.e) AND t3.a=t2.a AND
@ -3744,7 +3744,7 @@ EXPLAIN SELECT * FROM t1
WHERE ID_better=1 AND ID1_with_null IS NULL AND
(ID2_with_null=1 OR ID2_with_null=2);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref|filter idx1,idx2 idx1|idx2 5|4 const 2 (1%) Using index condition; Using where; Using rowid filter
1 SIMPLE t1 ref idx1,idx2 idx2 4 const 2 Using where
DROP TABLE t1;
CREATE TABLE t1 (a INT, ts TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, KEY ts(ts));
INSERT INTO t1 VALUES (30,"2006-01-03 23:00:00"), (31,"2006-01-03 23:00:00");