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Update manual to explain JoinQueryset instead of JoinManager

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Maarten ter Huurne 2024-04-17 17:28:25 +02:00
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docs/managers.rst
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@ -86,11 +86,11 @@ it's safe to use as your default manager for the model.
.. _contributed by Jeff Elmore: https://jeffelmore.org/2010/11/11/automatic-downcasting-of-inherited-models-in-django/ .. _contributed by Jeff Elmore: https://jeffelmore.org/2010/11/11/automatic-downcasting-of-inherited-models-in-django/
JoinManager JoinQueryset
----------- ------------
The ``JoinManager`` will create a temporary table of your current queryset A ``JoinQueryset`` will create a temporary table containing its own query result
and join that temporary table with the model of your current queryset. This can and join that temporary table with the model it is querying. This can
be advantageous if you have to page through your entire DB and using django's be advantageous if you have to page through your entire DB and using django's
slice mechanism to do that. ``LIMIT .. OFFSET ..`` becomes slower the bigger slice mechanism to do that. ``LIMIT .. OFFSET ..`` becomes slower the bigger
offset you use. offset you use.
@ -102,8 +102,9 @@ offset you use.
# qs contains 10 objects, and there will be a much smaller performance hit # qs contains 10 objects, and there will be a much smaller performance hit
# for paging through all of first 2000 objects. # for paging through all of first 2000 objects.
Alternatively, you can give it a queryset and the manager will create a temporary Alternatively, you can give it another queryset and ``JoinQueryset`` will create
table and join that to your current queryset. This can work as a more performant a temporary table containing the result of the given queryset and
join that temporary table to itself. This can work as a more performant
alternative to using django's ``__in`` as described in the following alternative to using django's ``__in`` as described in the following
(`StackExchange answer`_). (`StackExchange answer`_).
@ -114,6 +115,8 @@ alternative to using django's ``__in`` as described in the following
.. _StackExchange answer: https://dba.stackexchange.com/questions/91247/optimizing-a-postgres-query-with-a-large-in .. _StackExchange answer: https://dba.stackexchange.com/questions/91247/optimizing-a-postgres-query-with-a-large-in
You can create a manager that produces ``JoinQueryset`` instances using ``JoinQueryset.as_manager()``.
.. _QueryManager: .. _QueryManager:
QueryManager QueryManager