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Redo Log Buffer - Online redo - Archived log - LGWR

ice_cold_aswinJun 24 2009 — edited Jun 25 2009
Hi,

It is stated in this document that redo entries will be put into Redo Log Buffer for all the changes (DMLs) made to the database (My question is when does it happen? after commit?).

And, in this link, they say both uncommitted and committed changes in the section Redo. But when you scroll down to the section Commit on the same link, After a commit, the log writer process (LGWR) will write redo log entries from the SGA (Log Buffer) into the online redo log file.

I am wondering how? When I tested on my database table which holds > 300,000 records, redo logs, and subsequently archive logs are generated (I did not commit the DML yet).

Now my question is, how far is the set of archivelogs will be useful at the time of recovery, if I rollback the changes? If Oracle skips these archivelogs, why should it generate it?

And, which section in the second link is correct?

Please help.

Thanks,
Aswin.
This post has been answered by unknown-698157 on Jun 24 2009
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Locked on Jul 23 2009
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