Re: odd postgresql performance (excessive lseek)

On Tue, Oct 19, 2010 at 8:25 AM, Merlin Moncure <mmoncure(at)gmail(dot)com> wrote:
> On Tue, Oct 19, 2010 at 9:10 AM, Jon Nelson <jnelson+pgsql(at)jamponi(dot)net> wrote:
>> No replies?
>>
>> This is another situation where using pread would have saved a lot of
>> time and sped things up a bit, but failing that, keeping track of the
>> file position ourselves and only lseek'ing when necessary would also
>> help. Postgresql was spending 37% of it's time in redundant lseek!
>
> 37% of cpu time?  Is that according to strace -T? how did you measure it?

Per the original post, it (redundant lseek system calls) accounted for
37% of the time spent in the kernel.

strace -f -p <pid> -c

--
Jon