The documentation provides no indication as to why you might want to use indexes

[django-issues@…]

Indexing is not an inherently straightforward and intuitive concept. There's plenty of material out there that suggests where you might want to apply database indexes, but the Django documentation doesn't suggest *anything*. ​Database access optimization suggests that it is a number one priority, and that you should use the information you have gleaned from profiling to decide what to index, but provides no methodology for applying that information. It's left to the reader's imagination to decide if they should add indexes to fields they read a lot or fields they change a lot or fields they do lookups by a lot or fields that have fish puns in their names.

I'd make some suggestions, but I am not qualified enough to write anything I'd be at all confident in.

[bbaja42]

Created pull request ​https://github.com/django/django/pull/2252

[Tim Graham]

As noted on the PR, I think we can probably do a bit better than just a link to Wikipedia's entry on database indexes. I wouldn't want to go into too much detail since indexing is a complex topic and is often database dependent, but some idea of where to start looking would be helpful.

[alextreme]

I've expanded upon the previous pull request to also document a rule-of-thumb (use indexes to speed up lookups). I have added your caveats on the topic of indexes, but this should be enough to point readers in the right direction.

​https://github.com/django/django/pull/2360

[Tim Graham <timograham@…>]

In 8e704b176f30c9c208a45125d8f36319cf1aafa8:

[1.6.x] Fixed #21986 -- Added some guidelines for database indexes.

Thanks django-issues at colons.co for the suggestion.

Backport of c8d61fa109 from master