#30842: Prefetch_related spends considerable time constructing querysets.
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Reporter: Alex Aktsipetrov | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: prefetch_related | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Description changed by Alex Aktsipetrov:
Old description:
> As part of the [https://code.djangoproject.com/ticket/26226 bugfix]
> django started constructing N+1 querysets during a typical
> prefetch_related call while only 2 sql queries are executed.
>
> This adds a noticeable slowdown. Attaching the flamegraph for queryset
> fetching 100 objects.
New description:
As part of the [https://code.djangoproject.com/ticket/26226 bugfix] django
started constructing N+1 querysets during a typical prefetch_related call
while only 2 sql queries are executed.
This adds a noticeable slowdown. Attaching the flamegraph for queryset
fetching 100 objects, roughly 2/3 of the time are spent there.
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Ticket URL: <https://code.djangoproject.com/ticket/30842#comment:1>
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