Documentation should clarify lazy nature of querysets

[Simon Willison]

I've answered a couple of comments in the documentation recently about QuerySet lazy evaluation:

​http://www.djangoproject.com/documentation/tutorial4/#c2024
​http://www.djangoproject.com/documentation/models/pagination/#c2032

That's enough for me to think that this is a frequent misunderstanding. We certainly don't want people to be put off Django because they think it makes horribly inefficient queries, when the exact opposite is true!

An entry in the FAQ would be a good start, but having notes (and a link) about this behaviour in the relevant places in the docs would be smart too.

[James Bennett <ubernostrum@…>]

So a link from various places to this: ​http://www.djangoproject.com/documentation/db_api/#querysets-are-lazy might solve it?

[Simon G. <dev@…>]

Where should this be mentioned? possibly the best place would be to have a chained filter example in tutorial 1 and a comment/link to the db-api doc.

[James Bennett]

Patch adding an explanation that all() doesn't query

[Jacob]

(In [4637]) Fixed #2565: added a note about the laziness of querysets in tutorial 4. Thanks, Ubernostrum.