Have a look at the DatabaseOperations.max_in_list_size method, but it sounds like it's not going to be a simple constant for MySQL. On Oct 3, 2011 1:01 PM, "Cal Leeming [Simplicity Media Ltd]" < cal.leem...@simplicitymedialtd.co.uk> wrote: > Ahh - max_allowed_packet pops up its ugly head again - it > wouldn't surprise me if this was the case. > > Thank you for testing this against Postgre - I will post the test results > against MySQL tonight/tomorrow. > > Cal > > On Mon, Oct 3, 2011 at 7:58 PM, Jacob Kaplan-Moss <ja...@jacobian.org >wrote: > >> On Mon, Oct 3, 2011 at 1:31 PM, Cal Leeming [Simplicity Media Ltd] >> <cal.leem...@simplicitymedialtd.co.uk> wrote: >> > So, came up against a strange thing today. >> > Database backend is MySQL 5.5 (Percona variant) >> > >> > If I attempt to do an __in query with a list containing 50 thousand >> entries, >> > the query wouldn't fail, but would instead return no results. If I split >> it >> > up into chunks (say 100) - it would work fine. >> > For example: >> > _list = ['user1', 'user2'] # imagine this list has exactly 50 thousand >> > entries >> > Members.objects.filter(username__in = _list) # no results >> > Members.objects.filter(username__in = _list[:100]) # 100 results >> > I can provide exact further info, but this was just a preliminary email >> to >> > see if this was expected behavior - or actually a bug?? >> >> I'm guessing it's MySQL being "special" again. I tried IN queries with >> 100k arguments on postgres and it worked fine. The MySQL documentation >> states that "The number of values in the IN list is only limited by >> the max_allowed_packet value." >> ( >> http://dev.mysql.com/doc/refman/5.5/en/comparison-operators.html#function_in >> ), >> so perhaps investigate this max_allowed_packet setting? >> >> Jacob >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Django developers" group. >> To post to this group, send email to django-developers@googlegroups.com. >> To unsubscribe from this group, send email to >> django-developers+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/django-developers?hl=en. >> >> > > -- > You received this message because you are subscribed to the Google Groups "Django developers" group. > To post to this group, send email to django-developers@googlegroups.com. > To unsubscribe from this group, send email to django-developers+unsubscr...@googlegroups.com. > For more options, visit this group at http://groups.google.com/group/django-developers?hl=en. >
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