From: | Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> |
---|---|
To: | Ivan Voras <ivoras(at)freebsd(dot)org> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: Understanding tsearch2 performance |
Date: | 2010-07-14 13:25:27 |
Message-ID: | Pine.LNX.4.64.1007141722480.32129@sn.sai.msu.ru |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
On Wed, 14 Jul 2010, Ivan Voras wrote:
>> Returning 8449 rows could be quite long.
>
> You are right, I didn't test this. Issuing a query which returns a
> smaller result set is much faster.
>
> But, offtopic, why would returning 8500 records, each around 100 bytes
> long so around 8.5 MB, over local unix sockets, be so slow? The machine
> in question has a sustained memory bendwidth of nearly 10 GB/s. Does
> PostgreSQL spend much time marshalling the data through the socket stream?
It's disk access time.
in the very bad case it could take ~5 ms (for fast drive) to get one just
one row.
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
From | Date | Subject | |
---|---|---|---|
Next Message | Ivan Voras | 2010-07-14 13:37:56 | Re: Understanding tsearch2 performance |
Previous Message | Ivan Voras | 2010-07-14 12:55:36 | Re: Understanding tsearch2 performance |