Re: postgres 9.3 vs. 9.4

On Sep 18, 2014 9:32 PM, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
>
>
> On 09/18/2014 03:09 PM, Mkrtchyan, Tigran wrote:
> >
> > ----- Original Message -----
> >> From: "Josh Berkus" <josh(at)agliodbs(dot)com>
> >> To: pgsql-performance(at)postgresql(dot)org
> >> Sent: Thursday, September 18, 2014 7:54:24 PM
> >> Subject: Re: [PERFORM] postgres 9.3 vs. 9.4
> >>
> >> On 09/18/2014 08:09 AM, Mkrtchyan, Tigran wrote:
> >>>>> 9.4beta2:
> >>>>> ...
> >>>>>
> >>>>>>>          0.957854        END;
> >>>>>>>
> >>>>> Looks like IO.
> >>> Postgres internal IO? May be. We get 600MB/s on this SSDs.
> >> While it's possible that this is a Postgres issue, my first thought is
> >> that the two SSDs are not actually identical.  The 9.4 one may either
> >> have a fault, or may be mostly full and heavily fragmented.  Or the Dell
> >> PCIe card may have an issue.
> >
> > We have tested both SSDs and they have identical IO characteristics and
> > as I already mentioned, both databases are fresh, including filesystem.
> >
> >> You are using "scale 1" which is a < 1MB database, and one client and 1
> >> thread, which is an interesting test I wouldn't necessarily have done
> >> myself.  I'll throw the same test on one of my machines and see how it does.
> > this scenario corresponds to our use case. We need a high transaction rate
> > per for a single client. Currently I can get only ~1500 tps. Unfortunately,
> > posgtress does not tell me where the bottleneck is. Is this is defensively
> > not the disk IO.
> >
> >
> >
>
>
> This is when you dig out tools like perf, maybe.

Do you have a better suggestions ?

>
> cheers
>
> andrew