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Changes between Version 1 and Version 2 of Ticket #25787, comment 3

v1	v2
1	1	If that executes lazily then I am ok with this, thank you.
2	2
3		However looking at the code for QuerySet it defines an {{{__iter__}}} method but no {{{__contains__}}} method and {{{__iter__}}} executes {{{_fetch_all}}}, which means instead of doing an {{{.exists()}}} query using {{{in}}} on a query set fetches a large number of objects and iterates over the result. This is very inefficient.
	3	However looking at the code for QuerySet it defines an {{{__iter__}}} method but no {{{__contains__}}} method and {{{__iter__}}} executes {{{_fetch_all}}}, which means instead of doing an {{{.exists()}}} query using {{{in}}} on a query set fetches a large number of objects and iterates over the result objects rather than using the database aided {{{.exists()}}}.
	4	This is very inefficient.