| DBWR In Action [message #64066] |
Sat, 11 December 2004 06:40  |
M. Pallas
Messages: 12
Registered: November 2004
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Junior Member |
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For fun I ran a little experiment to see DBWR in action. I wrote thousands of rows to a table and forced a checkpoint to see DBWR writing dirty buffers onto the datafile. There was no change in the date and time of the data file on the OS level (Win 2000). I observed changes on all redo log groups and control file but not the datafile containing the table I was writing onto. What surprised me is that the commit SCN writes to the header of the datafiles did not affect the time stamp of any of the datafiles. It was only on shutdown that all datafile and logs took the OS time.
Can some one shed a little light on this; I am beginning to loose faith in the Oracle folks.
Many Thanks,
M. Pallas
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| Re: DBWR In Action [message #64070 is a reply to message #64066] |
Sun, 12 December 2004 21:13  |
Frank
Messages: 7901
Registered: March 2000
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Senior Member |
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(Try this on a test-db ;))
Start your database.
Open one of the database-files (dbf) in your editor and start editing.
What happens? The file is locked. So, Oracle does write to the file, but keeps it open. The timestamp of the file apparently only changes when it is closed. That's why all dbf-files have the same timestamp.
BTW, what difference does it make anyway what timestamp the datafiles got ??
hth
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| Re: DBWR In Action [message #64071 is a reply to message #64070] |
Sun, 12 December 2004 21:25 |
M. Pallas
Messages: 12
Registered: November 2004
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Junior Member |
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But the same thing happens if you open a redo log or a control file and attempt to write on either one. The OS locks those too and you caint write on them, but still changes them at the time Oracle writes on them. It is still a mystry to me when the write on the data files happens.
Thank you for the help Frank. I appreciate it. Maria.
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| how to enable audit trails in oracle 8i onwards [message #64072 is a reply to message #64071] |
Sun, 12 December 2004 23:26 |
nag raj
Messages: 4
Registered: December 2004
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Junior Member |
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hello
i want to know the transactions done in a particular period of time. i heared that these details will be stored in audit trails but i don't know how to enable these audit trails and where and how that information will be stored.
is there any alternate way to get that information( i mean transaction details)
many thanks
nag raj (salmon_002@yahoo.co.in)
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