#13906: REPEATABLE READ (as used by default on MySQL) breaks atleast
QuerySet.get_or_create().
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Reporter: sebastian_noack | Owner: nobody
Status: new | Milestone:
Component: Database layer (models, ORM) | Version: 1.2
Resolution: | Keywords:
Stage: Unreviewed | Has_patch: 0
Needs_docs: 0 | Needs_tests: 0
Needs_better_patch: 0 |
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Changes (by akaariai):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Comment:
Setting transaction level to READ COMMITED does not solve your problem. A
sequence showing erroneous behaviour in REPEATABLE READ:
t1: SELECT * FROM foo WHERE condition # transaction 1 get part.[[BR]]
t1: INSERT INTO ... # create[[BR]]
t2: SELECT * FROM foo WHERE condition # transaction 2 get part, t2 sees
nothing here.[[BR]]
t1: commit()[[BR]]
What would (at least partly) solve your problem is unique index on the
where condition, then the DB would be able to block the t2's create.
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Ticket URL: <http://code.djangoproject.com/ticket/13906#comment:1>
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