Add index in object_id column in LogEntry table to make fetch query faster.

[Shashank Parekh]

In history_view function, we use object_id and content_type to fetch the logs. Usually, we will have lots of entries based on content_type compare with object_id.

It is ideal to index object_id to make fetch query faster.

I can work on this task.

[Carlton Gibson]

Hi Shashank.

Without really looking, this seems reasonable.

What's the query being generated? Is that using a table scan? If so, you're just talking about adding an index right?

[Simon Charette]

If we decide to add an index we should consider a composite (content_type_id, object_id) one and maybe make the content_type foreign key db_index=False given there's no use case for querying LogEntry by object_id without content_type_id and that most (if not all) supported database engines are able to use the first parts of a composite index rendering the content_type_id index useless.

[Tim Graham]

Seems related to #23435: "GenericForeignKey should be indexed".

[Claude Paroz]

I think this is a duplicate of #17659 (blocked because object_id is a TextField currently unindexable on MySQL). See also #28661.