Re: What MB/s is pulled from your buffer cache?

From: Martin Klier <>
Date: Tue, 12 Feb 2013 22:10:44 +0100
Message-ID: <>

Hi Rich,

Rich Jesse schrieb:
> In our production DB, I was looking at v$sysstat, and happened to
> order the view by VALUE DESC for kicks. The highest number is for the
> 'logical read bytes from cache' stat and is currently over 500TB. That
> seems abnormally large for less than 2 months of our ~800GB DB, so I thought
> I'd see what that boils down to in MB/s:
> It's over 100MB/s, which my knee jerk (emphasis on the latter) tells me that
> this seems abnormally high for our li'l DB.
> I'm curious to see how that number compares to other installations, if folks
> are willing.

This heavily depends on the quality of your execution plans - have a look at SQL "SQL ordered by Buffer Gets" in AWR/Statspack reports. I don't think that number to be abnormally high...


---------------- ------------------- --------------------- -----------
-------------- -------------
         2.5E+16         23261681.06 16.12.2012 18:11:49         58.16
      5025448    4970112087

The DB is less than 2TB.


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Received on Tue Feb 12 2013 - 22:10:44 CET

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