Re: 8.1beta3 performance

On 1/11/05 2:50 pm, "Jon Brisbin" <jon(dot)brisbin(at)npcinternational(dot)com> wrote:

> On Mon, 31 Oct 2005 17:16:46 -0600
> "PostgreSQL" <martin(at)portant(dot)com> wrote:
>
>> We're running 8.1beta3 on one server and are having ridiculous
>> performance issues. This is a 2 cpu Opteron box and both processors
>> are staying at 98 or 99% utilization processing not-that-complex
>> queries. Prior to the upgrade, our I/O wait time was about 60% and
>> cpu utilization rarely got very high, now I/O wait time is at or near
>> zero.
>>
>> I'm planning to go back to 8.0 tonight or tomorrow night but thought
>> I'd check the pqsql-performance prophets before I gave it up.
>
> I have a stock FreeBSD 5.4 box that I put 8.1 on last night. I ran
> pgbench against it and my tps dropped from ~300tps in 8.0.3 to 20tps
> in 8.1. That's right. 20. No changes in any system configuration. No
> data in the new 8.1 database, only the pgbench init'ed stuff. 25
> clients, 100 and 1000 transactions with a scaling factor of 10, which
> gives me 1,000,000 tuples to shoot through.
>
> I wiped out the 8.1 installation, put 8.0.4 in it's place, and
> pgbenched it again. ~300tps again.
>
> It's not a problem with system configuration if 8.0 works fine, but 8.1
> has problems, unless there is something that 8.1 needs tweaked that 8.0
> doesn't. In that case, I just need to know what that is and I can tweak
> it.

Hi Jon,

Did you run the bundled version of pgbench against it's own installation?
There we some changes to pgbench for 8.1, and I have to wonder (bearing in
mind I haven't really looked at them) whether they could be affecting things
in any way. Do you get comparable results running the 8.0 pgbench against
both server versions?

Regards, Dave