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: [email protected] [mailto:[email protected]] On > Behalf Of Ivo Brodien > Sent: 01 February 2011 23:49 > To: [email protected] > 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#sysvar_optimizer_search_depth > > 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 [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://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 [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://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 [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
