Re: SGA & shared pool size

  • From: LS Cheng <exriscer@xxxxxxxxx>
  • To: veeeraman@xxxxxxxxx
  • Date: Fri, 16 Apr 2010 09:13:49 +0200


I configured one a few weeks ago with 48G SGA and 22GB shared pool for a

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.



On Fri, Apr 16, 2010 at 3:55 AM, Ram Raman <veeeraman@xxxxxxxxx> 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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