got it, thanks! without your help I really have no idea what should be fast and what supposed to be slower.
I also find "select" involves a lot of writes:
iotop shows:
2789 be/4 postgres 0.00 B 57.34 M 0.00 % 0.00 % postgres: goov conta 192.168.1.129(27300) SELECT
I knew that select could cause writes, but not at this magnitude....
On Fri, Jul 13, 2012 at 2:53 AM, Jeff Janes
<jeff.janes@gmail.com> wrote:
On Thu, Jul 12, 2012 at 9:07 AM, Ants Aasma <
ants@cybertec.at> wrote:
> On Thu, Jul 12, 2012 at 3:48 PM, Yan Chunlu <
springrider@gmail.com> wrote:
>> yes the system seems overloaded, I am dealing with a simple "INSERT" but not
>> sure if it is normal that it took more time than the explain estimated:
>
> The estimated cost is in arbitrary units, its purpose is to compare
> different execution plans, not estimate time taken. So it's completely
> normal that it doesn't match actual time taken.
to do something (like insert a row, or do maintenance on an index) it
often doesn't even attempt to cost that at all as there is no choice.
So it is not just a matter of units.
Cheers,
Jeff