database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

MDEV-29662 Replace same values in 'IN' list with an equality

Browse Source 
If all elements in the list of 'IN' or 'NOT IN' clause are equal
and there are no NULLs then clause
-  "a IN (e1,..,en)" can be converted to "a = e1"
-  "a NOT IN (e1,..,en)" can be converted to "a <> e1".
This means an object of Item_func_in can be replaced with an object
of Item_func_eq for IN (e1,..,en) clause and Item_func_ne for
NOT IN (e1,...,en). Such a replacement allows the optimizer to choose
a better execution plan
This commit is contained in:
Oleg Smirnov
2022-10-04 16:45:51 +07:00
parent b7fe6179e8
commit 5027cb2b74
8 changed files with 484 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
mysql-test/suite/innodb/r/innodb_mysql.result
View File

@ -2190,7 +2190,7 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED t1 ref c3,c2 c3 5 const 2 Using where; Using filesort
2 DERIVED t1 ref c3,c2 c3 5 const 2 Using where
DROP TABLE t1;
CREATE TABLE t1 (c1 REAL, c2 REAL, c3 REAL, KEY (c3), KEY (c2, c3))
ENGINE=InnoDB;
@ -2204,7 +2204,7 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED t1 ref c3,c2 c3 9 const 2 Using where; Using filesort
2 DERIVED t1 ref c3,c2 c3 9 const 2 Using where
DROP TABLE t1;
CREATE TABLE t1 (c1 DECIMAL(12,2), c2 DECIMAL(12,2), c3 DECIMAL(12,2),
KEY (c3), KEY (c2, c3))
@ -2219,7 +2219,7 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED t1 ref c3,c2 c3 7 const 2 Using where; Using filesort
2 DERIVED t1 ref c3,c2 c3 7 const 2 Using where
DROP TABLE t1;
End of 5.1 tests
#