Re: SGA & shared pool size

From: LS Cheng <exriscer_at_gmail.com>
Date: Fri, 16 Apr 2010 09:13:49 +0200
Message-ID: <g2p6e9345581004160013p4f1d630en2c1e99aa8c68e66d_at_mail.gmail.com>



Hi

I configured one a few weeks ago with 48G SGA and 22GB shared pool for a DWH. I think I hit some bug that is why I need to set the shared pool so large because this is a 6 nodes RAC and whenever shared pool is under pressure process LCK starts to free shared pool memory (observed from v$rowcache and v$sgastat) and holds the shared pool latch which cause hang in the node (sometimes the entire system, all 6 nodes). Previously I had shared pool set to 8GB and the hang situation happened everyday (many times instance dies), when I increased to 22GB it only happens like once every couple of weeks.

v$rowcache shows 7 million entries, anyone seen larger than that? I am really curious.

Thanks

--
LSC




On Fri, Apr 16, 2010 at 3:55 AM, Ram Raman <veeeraman_at_gmail.com> wrote:


>
> I saw a big database today with an SGA size of 56GB and a shared pool of
> 12Gb. The SGA_TARGET was set to 0. This database size is a few terabytes. I
> have not heard of such big SGA or SP sizes. I thought having big memory
> sizes may cause latch contention and CPU issues.
>
> What is the maximum SGA and SP sizes of DBs that you have seen.
>
> Thanks.
>
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Received on Fri Apr 16 2010 - 02:13:49 CDT

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