Opened 23 months ago
Closed 23 months ago
#34249 closed Cleanup/optimization (duplicate)
Custom RelatedManager documentation should have side tip on prefetch_related
| Reported by: | Vaughn Koch | Owned by: | nobody |
|---|---|---|---|
| Component: | Documentation | Version: | 4.1 |
| Severity: | Normal | Keywords: | documentation relatedmanager custom prefetch_related |
| Cc: | Triage Stage: | Unreviewed | |
| Has patch: | no | Needs documentation: | no |
| Needs tests: | no | Patch needs improvement: | no |
| Easy pickings: | no | UI/UX: | no |
Description
This Django documentation shows how to use a custom manager for reverse relations.
https://docs.djangoproject.com/en/4.1/topics/db/queries/#using-custom-reverse-manager
In the given example, this works well as-is, but if you prefetch_related the entries when you're querying Blog, Django will use the prefetch_related cache and ignore the custom manager.
This behavior may/may not be desired, but the documentation could use a side tip about this condition, maybe in a 'Good to know' infobox.
Also, separately: one flaw in the documented approach is that you have to explicitly use the custom manager when making a query - there doesn't seem to be a way to make the custom manager the default, which can cause issues if you forget to add it to all your calls.
Change History (1)
comment:1 by , 23 months ago
| Easy pickings: | unset |
|---|---|
| Resolution: | → duplicate |
| Status: | new → closed |
Duplicate of #30355.