Re: high 'gc current block pin time'

From: K Gopalakrishnan <kaygopal_at_gmail.com>
Date: Wed, 13 Apr 2011 18:38:44 -0500
Message-ID: <BANLkTiksrbhYspAAfmyjOFq6YLOcTLxnBg_at_mail.gmail.com>



Lei,

A high(er) average of current block pin time normally indicates higher level of concurrency of the block level. In some cases this could be associated with high incidence of deferred the block shipping by the holding instance. This is configurable via _gc_defer_time ( and no tweaking required for most of the cases) and typically observed from index blocks.

So to answer your question, investigate the segment statistics for high current block transfers and tune them.

-Gopal

On Wed, Apr 13, 2011 at 5:56 PM, Lei Zeng <lzeng_at_yahoo-inc.com> wrote:

> Hi, list:
>
>
>
> I noticed that one of our RAC (10.2.0.4) shows 4 digits in ‘gc current
> block pin time’ of AWR.
>
> Avg global cache current block pin time (ms): 2,717.7
>
>
>
> Other than this, there was no other gc level stats >20 ms.
>
>
>
> I searched this but I couldn’t find much information. What problem it is
> trying to tell me? Which direction I should look?
>
>
>
> Thanks,
>
> Lei
>
>
>
>
>

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Received on Wed Apr 13 2011 - 18:38:44 CDT

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