Circular joins are indeed a very likely reason which usually points to a poor model design. In fact I ran into the same problem just yesterday. I hooked Django admin to a legacy app that had a related field to table A and related field to table B that was also related to A. And that created an ever running query from the admin. As changing db structure was not feasible I had to remove those fields from my list_display to make it useable.
Also when you have a query hanging like that, inside MySQL shell you can run `show processlist` and then `kill <mysql_process_id>` to get rid of the offending query. Cheers Sergiy On Feb 3, 6:59 am, Ivo Brodien <i...@brodien.de> wrote: > Hi Chris, > > thanks for the info. My tables won’t have many rows and I don’t have the time > for optimazation, especially if it is not necessary, but I will keep your > words in mind! > > Cheers > Ivo > > On 02.02.2011, at 06:10, Chris Matthews wrote: > > > > > > > > > Hi Ivo, > > > SQL is like regular expressions. You can go complex (with one mega > > query/expression) but it could create a maintenance nightmare. See if you > > cannot simplify the query into multiple queries and a bit of code (for > > loops and using the joining columns) to lash them together. The code > > sequence should be such that you limit access to a huge amount of rows; so > > you filter the data accessed. It is usually easier to debug as well. And > > using Tom's advice (EXPLAIN SELECT ...) on smaller join queries is often > > more useful (than the explain on a mega join query). > > > In my experience it often runs way faster if the query is simplified. > > > Regards > > Chris > > -----Original Message----- > > From: django-users@googlegroups.com [mailto:django-users@googlegroups.com] > > On Behalf Of Ivo Brodien > > Sent: 01 February 2011 23:49 > > To: django-users@googlegroups.com > > Subject: Re: Django SQL Query does not stop > > > I found a solution be changing the MySQL server setting > > optimizer_search_depth to 3 (default 62) > > >http://dev.mysql.com/doc/refman/5.0/en/controlling-optimizer.html > >http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#s... > > > My query had over 20 INNER JOINTS and it made the optimizer search a long > > process. > > > So at the moment a value of 3 is fine. > > > On 01.02.2011, at 21:20, Ivo Brodien wrote: > > >> The Change List that I am calling is a Intermediate Table if that is of > >> any interest. > > >> Is it possible that there is some sort of circular inner joints or > >> something? > > > -- > > You received this message because you are subscribed to the Google Groups > > "Django users" group. > > To post to this group, send email to django-users@googlegroups.com. > > To unsubscribe from this group, send email to > > django-users+unsubscr...@googlegroups.com. > > For more options, visit this group > > athttp://groups.google.com/group/django-users?hl=en. > > > -- > > You received this message because you are subscribed to the Google Groups > > "Django users" group. > > To post to this group, send email to django-users@googlegroups.com. > > To unsubscribe from this group, send email to > > django-users+unsubscr...@googlegroups.com. > > For more options, visit this group > > athttp://groups.google.com/group/django-users?hl=en. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
