Re: Impact of checkpoint_segments under continual load conditions

On 7/19/05, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Christopher Petrilli <petrilli(at)gmail(dot)com> writes:
> > On 7/19/05, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> How *exactly* are you invoking psql?
>
> > It is a subprocess of a Python process, driven using a pexpect
> > interchange. I send the COPY command, then wait for the '=#' to come
> > back.
>
> Some weird interaction with pexpect maybe? Try adding "-n" (disable
> readline) to the psql command switches.

Um... WOW!

==> pgsql_benchmark_803_bigbuffers10000_noreadline.txt <==
0 0.0319459438324 0.0263829231262
1 0.0303978919983 0.0263390541077
2 0.0306499004364 0.0273139476776
3 0.0306959152222 0.0270659923553
4 0.0307791233063 0.0278429985046
5 0.0306351184845 0.0278820991516
6 0.0307800769806 0.0335869789124
7 0.0408310890198 0.0370559692383
8 0.0371310710907 0.0344209671021
9 0.0372560024261 0.0334041118622

==> pgsql_benchmark_803_bigbuffers10000.txt <==
0 0.0352520942688 0.149132013321
1 0.0320160388947 0.146126031876
2 0.0307128429413 0.139330863953
3 0.0306718349457 0.139590978622
4 0.0307030677795 0.140225172043
5 0.0306420326233 0.140012979507
6 0.0307261943817 0.139672994614
7 0.0307750701904 0.140661001205
8 0.0307800769806 0.141661167145
9 0.0306720733643 0.141198158264

First column is iteration, second is "gen time" to generate the load
file, and 3rd is "load time".

It doesn't stay QUITE that low, but it stays lower... quite a bit.
We'll see what happens over time.

Chris
--
| Christopher Petrilli
| petrilli(at)gmail(dot)com