Re: What happens between end of explain analyze and end of query execution ? - Mailing list pgsql-performance

From Franck Routier
Subject Re: What happens between end of explain analyze and end of query execution ?
Date
Msg-id 515FD69F.8080805@axege.com
Whole thread Raw
In response to Re: What happens between end of explain analyze and end of query execution ?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Le 05/04/2013 16:17, Tom Lane a écrit :
> Franck Routier <franck.routier@axege.com> writes:
>> Le 04/04/2013 21:08, Tom Lane a écrit :
>>> Hmph.  Can't see any reason for that to take a remarkably long time to
>>> plan.  Can you put together a self-contained test case demonstrating
>>> excessive planning time?  What PG version is this, anyway?
>> What I notice is that removing joins has a huge impact on the time
>> explain takes to return:
> Hm, kind of looks like it's just taking an unreasonable amount of time
> to process each join clause.  What have you got the statistics targets
> set to in this database?  What are the datatypes of the join columns?
> And (again) what PG version is this exactly?
>
>             regards, tom lane
>
>
Postgresql version is 8.4.8.
Value for default_statistics_target is 5000 (maybe this is the problem ?)
Join columns datatypes are all varchar(32).

Also notice that not all joins have equals imppact on the time taken:
removing join on some tables has no impact (sanact, rsaidp), while
removing joins on others (saneds, sandia) has an important effect...

Regards,
Franck


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