[Django] #24296: clear select fields for `.exists()` of distinct, non-sliced querysets
Django
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Reporter: outofculture | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Database layer (models, ORM) | Version: 1.7
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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The fix (93cc6dcdac6fc3e506640fa38dd1798c3cd61cff) for bug #18414
introduced an inefficiency in `.exists()` on distinct querysets in that
now all distinct querysets are selecting all their fields. I propose the
fields should be left on the queryset only if `(q.distinct and
(q.high_mark is not None or q.low_mark is not None))`.
As I started writing the test for this, I realized I would have to inspect
the query itself, which seems... like a bad idea for a test. Would this be
reasonable to submit the (one-line-change) patch without a test, or does
someone have a suggestion for a way to make the test that's less brittle?
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Ticket URL: <https://code.djangoproject.com/ticket/24296>
Django <https://code.djangoproject.com/>
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Django
Reporter: outofculture | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.7
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* needs_better_patch: => 0
* needs_docs: => 0
* needs_tests: => 0
* stage: Unreviewed => Accepted
Comment:
A test that inspects the query is likely fine. See if you can find an
existing test that does something similar.
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Ticket URL: <https://code.djangoproject.com/ticket/24296#comment:1>
Django
Reporter: Martin Chase | Owner: Marcelo
Type: | Galigniana
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 1.7
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Marcelo Galigniana):
* owner: nobody => Marcelo Galigniana
* status: new => assigned
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Ticket URL: <https://code.djangoproject.com/ticket/24296#comment:2>
Django
Reporter: Martin Chase | Owner: Marcelo
Type: | Galigniana
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 1.7
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Marcelo Galigniana):
[https://github.com/django/django/pull/15576 PR was created]
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Ticket URL: <https://code.djangoproject.com/ticket/24296#comment:3>
Django
Reporter: Martin Chase | Owner: Marcelo
Type: | Galigniana
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 1.7
(models, ORM) |
Severity: Normal | Resolution:
| checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Mariusz Felisiak):
* has_patch: 0 => 1
* stage: Accepted => Ready for checkin
--
Ticket URL: <https://code.djangoproject.com/ticket/24296#comment:4>
Django
Reporter: Martin Chase | Owner: Marcelo
Type: | Galigniana
Component: Database layer | Version: 1.7
(models, ORM) |
Keywords: | Triage Stage: Ready for
| checkin
Has patch: 1 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Mariusz Felisiak <felisiak.mariusz@…>):
* status: assigned => closed
* resolution: => fixed
Comment:
In [changeset:"0ad5316f22eabe8fa8b22dc92e61170cfacc3c78" 0ad5316f]:
{{{
#!CommitTicketReference repository=""
revision="0ad5316f22eabe8fa8b22dc92e61170cfacc3c78"
Fixed #24296 -- Made QuerySet.exists() clear selected columns for not
sliced distinct querysets.
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/24296#comment:5>