#18676: Django should do m2m deletes in a single query when possible
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Reporter: jdunck | Owner: nobody
Type: | Status: new
Cleanup/optimization | Version: 1.4
Component: Database layer | Resolution:
(models, ORM) | Triage Stage: Accepted
Severity: Normal | Needs documentation: 0
Keywords: | Patch needs improvement: 0
Has patch: 1 | UI/UX: 0
Needs tests: 0 |
Easy pickings: 0 |
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Changes (by akaariai):
* has_patch: 0 => 1
Comment:
I am going to hijack this ticket for "fast-path" deletion. This is in
effect for any model that:
- does not have signals attached for pre/post delete (or m2m_changed, if
the model happens to be m2m model).
- does not lead to further cascades (all cascades except DO_NOTHING
prevent the fast path).
- do not have parents (this is a special case of reverse-cascade).
I have a patch at https://github.com/akaariai/django/tree/fast_delete for
this. I think it is ready for 1.5 inclusion.
The patch is in two commits:
-
[https://github.com/akaariai/django/commit/93bf3309ad4b9ee90ea953658ae444a0deea24ec
A way to check if there are signals for a model]
-
[https://github.com/akaariai/django/commit/3c2fce6bdb82d27b153e8061888ec6514795f88c
The actual fast path deletion code].
If nothing surprising arises, I will push this into 1.5 before feature
freeze.
--
Ticket URL: <https://code.djangoproject.com/ticket/18676#comment:2>
Django <https://code.djangoproject.com/>
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