From: Andy Colson <andy@squeakycode.net>
To: Rajesh Kumar. Mallah <mallah@tradeindia.com>
Cc: Claudio Freire <klaussfreire@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: High load average in 64-core server , no I/O wait and CPU is idle
Date: Thu, 24 May 2012 07:48:14 -0500
Message-ID: <4FBE2E0E.9050108@squeakycode.net> (raw)
In-Reply-To: <32382476.226771337837207313.JavaMail.root@zmbox01.trade-india-local.com>
References: <32382476.226771337837207313.JavaMail.root@zmbox01.trade-india-local.com>
On 05/24/2012 12:26 AM, Rajesh Kumar. Mallah wrote:
>
> ----- "Claudio Freire"<klaussfreire@gmail.com> wrote:
>
> | From: "Claudio Freire"<klaussfreire@gmail.com>
> | To: "Rajesh Kumar. Mallah"<mallah@tradeindia.com>
> | Cc: pgsql-performance@postgresql.org
> | Sent: Thursday, May 24, 2012 9:23:43 AM
> | Subject: Re: [PERFORM] High load average in 64-core server , no I/O wait and CPU is idle
> |
> | On Thu, May 24, 2012 at 12:39 AM, Rajesh Kumar. Mallah
> |<mallah@tradeindia.com> wrote:
> |> The problem is that sometimes there are spikes of load avg which
> |> jumps to> 50 very rapidly ( ie from 0.5 to 50 within 10 secs) and
> |> it remains there for sometime and slowly reduces to normal value.
> |>
> |> During such times of high load average we observe that there is no
> | IO wait
> |> in system and even CPU is 50% idle. In any case the IO Wait always
> | remains< 1.0 % and
> |> is mostly 0. Hence the load is not due to high I/O wait which was
> | generally
> |> the case with our previous hardware.
> |
> | Do you experience decreased query performance?
>
>
> Yes we do experience substantial application performance degradations.
>
>
Maybe you are hitting some locks? If its not IO and not CPU then maybe something is getting locked and queries are piling up.
-Andy
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To: pgsql-performance@postgresql.org
Cc: andy@squeakycode.net, mallah@tradeindia.com, klaussfreire@gmail.com
Subject: Re: High load average in 64-core server , no I/O wait and CPU is idle
In-Reply-To: <4FBE2E0E.9050108@squeakycode.net>
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