#26964: No mention of index_together on the GenericForeignKey section
-------------------------------+--------------------------------------
Reporter: aidanlister | Owner: nobody
Type: Bug | Status: new
Component: Documentation | Version: 1.9
Severity: Normal | Resolution:
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
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Description changed by aidanlister:
Old description:
> We've been troubleshooting a performance issue and noticed that there was
> no index on an important GenericForiegnKey.
>
> Once we'd resolved that, we noticed a contrib app had no index either
> (django reversion).
>
> It seems like this should be mentioned in the documentation here:
>
> https://docs.djangoproject.com/en/1.9/ref/contrib/contenttypes/#generic-
> relations
>
> Suggested wording:
>
> If you plan to search for child objects which have a generic relation to
> your parent object, e.g. find all tags linked to a piece of content, then
> you should consider adding a database index on the content type and
> object ID using index_together
> (https://docs.djangoproject.com/en/1.9/ref/models/options/#index-
> together). Django does not do this for you automatically as it does with
> ForeignKey's.
>
> In the example above, this would look like:
>
> <code>
> class Meta:
> index_together = [
> ["content_type", "object_id"],
> ]
> </code>
New description:
We've been troubleshooting a performance issue and noticed that there was
no index on an important GenericForiegnKey.
Once we'd resolved that, we noticed a contrib app had no index either
(django reversion).
It seems like this should be mentioned in the documentation here:
https://docs.djangoproject.com/en/1.9/ref/contrib/contenttypes/#generic-
relations
Suggested wording:
If you plan to search for child objects which have a generic relation to
your parent object, e.g. find all tags linked to a piece of content, then
you should consider adding a database index on the content type and object
ID using index_together
(https://docs.djangoproject.com/en/1.9/ref/models/options/#index-
together). Django does not do this for you automatically as it does with
ForeignKey's.
In the example above, this would look like:
```
class Meta:
index_together = [
["content_type", "object_id"],
]
```
--
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Ticket URL: <https://code.djangoproject.com/ticket/26964#comment:2>
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