RE: Automatic Shared Memory question

Armed with the information provided by Tanel, I went back to my SR with Oracle Support for more detail on "KGH: NO ACCESS" to see if I could get them to corroborate what we're seeing and here is the answer I was given:

"KGH: NO ACCESS chunks are owned by the buffer cache and indicate a partial transfer between buffer cache and shared pool."

I don't know why they couldn't tell me that the first time I asked - I guess it was top-secret until Tanel blew it :)

So, this means that unless they change things - it will be very common for sum(bytes) from v$sgastat to return a value significantly greater than your sga_max_size, and the difference will probably be roughly equal to the size consumed by "KGH: NO ACCESS". This KGH: NO ACCESS area should disappear completely after the instance is restarted - then occasionally grow and shrink as granules are passed back and forth between the shared pool and the buffer cache (if you are using Automatic Shared Memory Management, e.g. sga_target > 0).

Regards,
Brandon

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Tanel Poder Sent: Tuesday, August 22, 2006 10:17 PM
To: 'ORACLE-L'
Subject: RE: Automatic Shared Memory question

> I wonder if those buffers stored in the shared pool are being reported

> twice in v$sgastat - once under "KGH: NO ACCESS" and again under
> "buffer_cache"? That would explain why
> sum(bytes) from v$sgastat is so much larger than my sga_target &
> sga_max_size. I'll see if I can find a way to confirm this is what's
> happening . . .

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