RE: Unexpected behavior with V$FILESTAT
- From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
- To: <terrysutton@xxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 26 Aug 2005 14:52:54 -0700
>Is it possible that dbwriter hadn't yet written the blocks to disk when you
>performed your query?
>
>--Terry
Yep, that was the case - here is the off-list exchange I had with Mr. Kennedy:
-----Original Message-----
From: Kennedy, Jim [mailto:jim_kennedy@xxxxxxxxxx]
Sent: Friday, August 26, 2005 1:59 PM
To: Allen, Brandon
Subject: RE: Unexpected behavior with V$FILESTAT
Yup. That did it. Subtle but it makes sense.
Thanks,
Jim
-----Original Message-----
From: Allen, Brandon [mailto:Brandon.Allen@xxxxxxxxxxx]
Sent: Friday, August 26, 2005 1:58 PM
To: Kennedy, Jim
Subject: RE: Unexpected behavior with V$FILESTAT
If I understand correctly, a commit just ensures that it is written to
the redo log. Datafile writes are done by DBWR on its own time during
checkpoints. Try forcing a checkpoint and see if that forces the
phywrts to go up.
-----Original Message-----
From: Kennedy, Jim [mailto:jim_kennedy@xxxxxxxxxx]
Sent: Friday, August 26, 2005 1:39 PM
To: Allen, Brandon
Subject: RE: Unexpected behavior with V$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@xxxxxxxxxxx]
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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