Re: BUG #6426: Complex query runs 10 times longer with "LIMIT 20"

Hi Alex,

Thank you. I played with subqueries, but in this case I did not see a good
enough improvement.

In my specific case, what I've seen from the query execution plans, is that
without LIMIT the query uses Hash Joins, but once I add LIMIT, it starts
using Nested Loop Joins almost everywhere.

Regards,

Andrew

On Wed, Feb 1, 2012 at 9:42 PM, Alex Lai <alai(at)sesda2(dot)com> wrote:

> Hi Andrew,
> I posted for another post, its may give you a workaround.
> I still not fully understand how PG choose execute plan that slow down so
> much.
>
> I had the same situation in one of my query.
> Use the subquery can speed up almost by 100 times faster.
>
> ..........
>

> Hope this help.
>
>
> Best Regards,
> Alex Lai
>
> --
> Best regards,
>
>
> Alex Lai
> OMI SIPS DBA ADNET Systems , Inc. 7515 Mission Drive, Suite A100 Lanham,
> MD 20706 301-352-4657 (phone) 301-352-0437 (fax) alai(at)sesda2(dot)com
>
>

--
--
Andrew Schetinin