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RE: Unexpected behavior with V$FILESTAT

From: Allen, Brandon <Brandon.Allen_at_OneNeck.com>
Date: Fri, 26 Aug 2005 14:52:54 -0700
Message-ID: <04DDF147ED3A0D42B48A48A18D574C45023614DD@NT15.oneneck.corp>


>Is it possible that dbwriter hadn't yet written the blocks to disk when you
>performed your query?
>
>--Terry

Yep, that was the case - here is the off-list exchange I had with Mr. Kennedy:

-----Original Message-----
From: Kennedy, Jim [mailto:jim_kennedy_at_mentor.com] Sent: Friday, August 26, 2005 1:59 PM
To: Allen, Brandon
Subject: RE: Unexpected behavior with V$FILESTAT

Yup. That did it. Subtle but it makes sense. Thanks,
Jim

-----Original Message-----
From: Allen, Brandon [mailto:Brandon.Allen_at_OneNeck.com] Sent: Friday, August 26, 2005 1:58 PM
To: Kennedy, Jim
Subject: RE: Unexpected behavior with V$FILESTAT

If I understand correctly, a commit just ensures that it is written to the redo log. Datafile writes are done by DBWR on its own time during checkpoints. Try forcing a checkpoint and see if that forces the phywrts to go up.

-----Original Message-----
From: Kennedy, Jim [mailto:jim_kennedy_at_mentor.com] Sent: Friday, August 26, 2005 1:39 PM
To: Allen, Brandon
Subject: RE: Unexpected behavior with V$FILESTAT

Hmmm, could be.. But I would have expected the commit to make sure it was written to the datafile. I did several tests: Truncate table and reuse storage (so the high water mark isn't involved - reset it). Record the phywrites, insert data and commit. Keep querying the physical writes and not seeing the number go up. (times at least 30 seconds and not increase in physical write count.)

Odd, not what I expected the column to mean or behave. Jim

-----Original Message-----
From: Allen, Brandon [mailto:Brandon.Allen_at_OneNeck.com] Sent: Friday, August 26, 2005 1:26 PM
To: Kennedy, Jim
Subject: RE: Unexpected behavior with V$FILESTAT

Maybe all the writes were done in cache - not written to the file yet?

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Received on Fri Aug 26 2005 - 16:53:28 CDT

Original text of this message

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