Postgres Pro
Downloads
Home   >   mailing lists

Re: hash semi join caused by "IN (select ...)" - Mailing list pgsql-performance

From Tom Lane
Subject Re: hash semi join caused by "IN (select ...)"
Date
Msg-id 23922.1305588168@sss.pgh.pa.us
Whole thread Raw
In response to hash semi join caused by "IN (select ...)"  (Clemens Eisserer <linuxhippy@gmail.com>)
Responses Re: hash semi join caused by "IN (select ...)"
List pgsql-performance
Tree view 
Clemens Eisserer <linuxhippy@gmail.com> writes:
> I have a quite complex, performance sensitive query in a system with a
> few (7) joins:
> select .... from t1 left join t2 .... WHERE id IN (select ....)

Does it work as expected with one less join?  If so, try increasing
join_collapse_limit ...

            regards, tom lane

pgsql-performance by date:

Previous
From: Clemens Eisserer
Date:
Subject: hash semi join caused by "IN (select ...)"
Next
From: Dave Johansen
Date:
Subject: Re: hash semi join caused by "IN (select ...)"