#35241: Cache Model._meta.get_parent_list()
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Reporter: Adam Johnson | Owner: Adam
Type: | Johnson
Cleanup/optimization | Status: assigned
Component: Database layer | Version: dev
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
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Old description:
> Another candidate for caching, like #35230 and #35232, following the same
> system check profiling.
>
> `Model._meta.get_parent_list()` computes the flattened list of ancestor
> models by MRO. This list is immutable, deterministic, and recursively
> constructed through the inheritance hierarchy. These properties make it a
> prime candidate for caching.
>
> I found this method was taking ~1% of the total runtime for system checks
> on a project with 118 models. After adding caching, it’s reduced to a
> negligible amount.
>
> `get_parent_list()` is called in many other code paths, so caching will
> help all of those too.
New description:
Another candidate for caching, like #35230 and #35232, following the same
system check profiling.
`Model._meta.get_parent_list()` computes the flattened list of ancestor
models by MRO. This list is immutable, deterministic, and recursively
constructed through the inheritance hierarchy. These properties make it a
prime candidate for caching.
I found this method was taking ~1% (0.39ms) of the total runtime for
system checks on a project with 118 models. After adding caching, it’s
reduced to a negligible amount (<0.01ms).
`get_parent_list()` is called in many other code paths, so caching will
help all of those too.
--
Comment (by Adam Johnson):
I added concrete numbers to the description.
--
Ticket URL: <https://code.djangoproject.com/ticket/35241#comment:3>
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