Bug #50418 DROP PARTITION does not interact with transactions

Description:
DROP PARTITION does not wait or break concurrent transactions running in other threads, which breaks ACID (Isolation) on the other transactions.

How to repeat:
CREATE TABLE t1 (
id INT AUTO_INCREMENT NOT NULL,
name CHAR(50) NOT NULL,
myDate DATE NOT NULL,
PRIMARY KEY (id, myDate),
INDEX idx_date (myDate)
) ENGINE=InnoDB
PARTITION BY RANGE ( TO_DAYS(myDate) ) (
PARTITION p0 VALUES LESS THAN (734028),
PARTITION p1 VALUES LESS THAN (734029),
PARTITION p2 VALUES LESS THAN (734030),
PARTITION p3 VALUES LESS THAN MAXVALUE
) ;
INSERT INTO t1 VALUES 
(NULL, 'Lachlan', '2009-09-13'),
(NULL, 'Clint', '2009-09-13'),
(NULL, 'John', '2009-09-14'),
(NULL, 'Dave', '2009-09-14'),
(NULL, 'Jeremy', '2009-09-15'),
(NULL, 'Scott', '2009-09-15'),
(NULL, 'Jeff', '2009-09-16'),
(NULL, 'Joe', '2009-09-16');
SET AUTOCOMMIT=0;
SELECT * FROM t1 FOR UPDATE;
id	name	myDate
1	Lachlan	2009-09-13
2	Clint	2009-09-13
3	John	2009-09-14
4	Dave	2009-09-14
5	Jeremy	2009-09-15
6	Scott	2009-09-15
7	Jeff	2009-09-16
8	Joe	2009-09-16
UPDATE t1 SET name = 'Mattias' WHERE id = 7;
SELECT * FROM t1 WHERE id = 7;
id	name	myDate
7	Mattias	2009-09-16
# Connection con1
ALTER TABLE t1 DROP PARTITION p3;
SHOW WARNINGS;
Level	Code	Message
# Connection default
SELECT * FROM t1;
id	name	myDate
1	Lachlan	2009-09-13
2	Clint	2009-09-13
3	John	2009-09-14
4	Dave	2009-09-14
# Note that there are no errors or warnings that someone else have made changes.
COMMIT;
# No errors/warnings here either
DROP TABLE t1;

Suggested fix:
Before removing any (possibly used) partition, take an exclusive lock on either the partition (if possible) or on the table (i.e. name lock or any other exclusive lock).

Thank you for the report.

Verified as described.

Also related to bug#49907.

fix for 5.5 is included in the proposed patch for bug#53676 / bug#53770 here:
http://lists.mysql.com/commits/110773

Pushed into mysql-5.5 5.5.6-m3 (revid:alik@ibmvm-20100825092002-2yvkb3iwu43ycpnm) (version source revid:alik@ibmvm-20100825092002-2yvkb3iwu43ycpnm) (merge vers: 5.5.6-m3) (pib:20)

Pushed into mysql-trunk 5.6.1-m4 (revid:alik@sun.com-20100830082732-n2eyijnv86exc5ci) (version source revid:alik@sun.com-20100830082732-n2eyijnv86exc5ci) (merge vers: 5.6.1-m4) (pib:21)

Pushed into mysql-next-mr (revid:alik@sun.com-20100830082745-n6sh01wlwh3itasv) (version source revid:alik@sun.com-20100830082745-n6sh01wlwh3itasv) (pib:21)

Fixed in 5.5 by the patch for bug#53676.