From eed658d7c4dda695976c6845346b166960957eba Mon Sep 17 00:00:00 2001 From: Daniel Jilg Date: Wed, 6 Apr 2016 13:55:09 +0200 Subject: [PATCH] Refs #14131 -- Documented why paginating large QuerySets may be slow. --- docs/topics/pagination.txt | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/docs/topics/pagination.txt b/docs/topics/pagination.txt index 9baa1879e1..85612b734e 100644 --- a/docs/topics/pagination.txt +++ b/docs/topics/pagination.txt @@ -146,10 +146,12 @@ Required arguments clause or with a default :attr:`~django.db.models.Options.ordering` on the model. - .. note:: + .. admonition:: Performance issues paginating large ``QuerySet``\s - If you are using a ``QuerySet`` with a very large number of items, - requesting high page numbers might be slow on some database backends. + If you're using a ``QuerySet`` with a very large number of items, + requesting high page numbers might be slow on some databases, because + the resulting ``LIMIT``/``OFFSET`` query needs to count the number of + ``OFFSET`` records which takes longer as the page number gets higher. ``per_page`` The maximum number of items to include on a page, not including orphans