11gR2 DB Flash Cache

From: Jack Applewhite <jack.applewhite_at_austinisd.org>
Date: Tue, 7 Feb 2017 20:26:27 +0000
Message-ID: <MWHPR02MB23528B51E0B94957EA6D99FCE6430_at_MWHPR02MB2352.namprd02.prod.outlook.com>

We recently moved our busiest two 11gR2 EE databases (about 1TB each) from an X4 ODA to an X5. It was via switchover to physical standbys, so we hadn't been using - didn't really know about (no Flash Cache SSDs in X4s) - Database Smart Flash Cache. Last weekend we were able to configure each DB (one per node on the X5 ODA) to have 192GB Flash Cache (out of 512GB total available in the ODA).

Well, it's been better than Christmas! We've been marveling at the HUGE overall performance improvement we see. The main App hitting one of the DBs is a COTS Student Information System, hit by all of our 12,000 or so teachers and staff. There were a bunch of Selects in the App's code that would drive load averages to 200 - 400% periodically during the day. Now we rarely see load averages approaching 100%, usually staying around 25%. StatsPac reports show the dramatic differences in waits, as well as the SQLs found to be hogs.

My question ... Is there a way to get visibility into the flash cache to see what's in there? Since this is 11g, the 12c-only V$FlashFileStat view is not available and V$Sess_IO only has the session level Optimized_Physical_Reads column. None of the SGA-related views that I've found have info. about the flash cache. Mr. Google and MOS haven't helped either.

Any way to see what's going on in the Flash Cache?



Jack C. Applewhite - Database Administrator Austin I.S.D. - MIS Department
512.414.9250 (wk)

I can't help about the shape I'm in,
I can't sing, I ain't pretty and my legs are thin. But ... -- "Oh Well" F.M.

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http://www.freelists.org/webpage/oracle-l Received on Tue Feb 07 2017 - 21:26:27 CET

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