id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
7121	Slicing on QuerySet bypasses result_cache	lars@…	nobody	"Playing around in the shell and watching postgresql.log I found out the following:

Method a)
{{{
list = Article.objects.filter(id__gt=130).order_by('-id')[0:2]
list[0] # Performs SQL query with LIMIT 1
list[1] # Performs another SQL query with LIMIT 1 OFFSET 2
}}}

Method b) 

{{{
list = Article.objects.filter(id__gt=130).order_by('-id')[0:2]
list # Performs an SQL query with LIMIT 2
list[0] # Hits the cache
list[1] # Hits the cache
}}}

Calling {{{list[0]}}} afterwards will invoke the SQL query with LIMIT 1
   Calling {{{list[1]}}} after this will invoke another query with LIMT 1 OFFSET 1

b) Calling just ""list"" afterwards first and then calling {{{list[0]}}} and {{{list[1]}}}
   will honor the cache and therefore only one SQL query gets fired.


"		new	Uncategorized	dev			qsrf-cleanup queryset-rf, cache		Unreviewed	0	0	0	0	0	0