#2705: [patch] Add optional FOR UPDATE clause to QuerySets
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Reporter: Hawkeye | Owner: nobody
Status: new | Milestone:
Component: Database layer (models, ORM) | Version: SVN
Resolution: | Keywords:
Stage: Accepted | Has_patch: 1
Needs_docs: 0 | Needs_tests: 0
Needs_better_patch: 1 |
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Comment (by anih):
Replying to [comment:41 liangent]:
> Replying to [comment:37 anih]:
> (note: 1. 'key 1' is the primary key; 2. i'm using mysql:
5.0.67-0ubuntu6)
>
> i think it has nothing to do with the models.
>
> as i know, django try to SELECT a row when we're going to .save() to
know if the row exists. however, because i used SELECT FOR UPDATE, mysql
locked the row, and django cannot find it with SELECT, so django decides
to INSERT. since the field 'id' in object 't' has been set and value is
assigned to an existing row ('t' was got from a SELECT FOR UPDATE), an
IntegrityError is raised.
problem is how mysql treats rows select with for update statment:
http://www.mysqlperformanceblog.com/2006/08/06/select-lock-in-share-mode-
and-for-update/
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Ticket URL: <http://code.djangoproject.com/ticket/2705#comment:43>
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