| Bug #67806 | Multiple user level lock per connection | ||
|---|---|---|---|
| Submitted: | 4 Dec 2012 20:58 | Modified: | 1 Oct 2014 14:19 |
| Reporter: | Konstantin Osipov (OCA) | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: Locking | Severity: | S4 (Feature request) |
| Version: | 5.5 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
| Tags: | Contribution, MySQL, user level locks | ||
[4 Dec 2012 20:58]
Konstantin Osipov
[4 Dec 2012 20:59]
Sveta Smirnova
Thank you for the reasonable feature request.
[2 Apr 2013 9:09]
Konstantin Osipov
https://code.launchpad.net/~kostja/mysql-server/userlock Here's the patch ported to mysql-server branch.
[3 Apr 2013 12:08]
Konstantin Osipov
Multiple user locks per connections. (*) I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.
Contribution: 1.diff (text/x-patch), 47.63 KiB.
[11 Apr 2013 12:12]
Ståle Deraas
Hi Kostja, Thanks a lot for the contribution! We will work to have it included in trunk. /Staale
[26 Nov 2013 14:08]
Veniamin Gvodikov
affect me
[10 Dec 2013 10:20]
Eugene Kirdzei
affect me
[10 Dec 2013 10:27]
Alexey Rybak
Several days ago we celebrated 1st year anniversary of this patch. I still hope to see multiple user-level locks working correctly in MySQL. Please, accept this contribution.
[10 Dec 2013 12:24]
German Zvonchuk
affects me
[10 Dec 2013 14:04]
Euigene Klimov
affected me
[12 Dec 2013 6:59]
Alexey Manuhin
affects me
[22 Sep 2014 16:43]
Leandro Morgado
In 5.7.5 (not GA yet) documentation, we can find this: ===== Before 5.7.5, only a single simultaneous lock can be acquired and GET_LOCK() releases any existing lock. In MySQL 5.7.5, GET_LOCK() was reimplemented using the metadata locking (MDL) subsystem and its capabilities were extended. Multiple simultaneous locks can be acquired and GET_LOCK() does not release any existing locks. It is even possible for a given session to acquire multiple locks for the same name. Other sessions cannot acquire a lock with that name until the acquiring session releases all its locks for the name. As a result of the MDL reimplementation, locks acquired with GET_LOCK() appear in the Performance Schema metadata_locks table. The OBJECT_TYPE column says USER LEVEL LOCK and the OBJECT_NAME column indicates the lock name. Also, the capability of acquiring multiple locks introduces the possibility of deadlock among clients. An ER_USER_LOCK_DEADLOCK error is returned when this occurs. http://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock =====
[1 Oct 2014 14:19]
Dmitry Lenev
Hello! The patch based on this contribution became part of MySQL Server 5.7.5 Development Milestone Release. Documentation pages were updated accordingly (see http://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html). So I am closing this feature request. Thank you a lot for your contribution once again!
