Re: Confuse in Commited Data Pls Help

aman.oracle.dba wrote:
> Hello DBAs,
>
> Suppose, I am not committing my data since morning and doing so many
> entries.
> where
> database is in noarchivelog
> SGA size is 100M
> undo_retention is 900
> undo_tablespace size is 10M
> log groups are 3
> log switched since morning 15
>
> I already inserted data for 140M (which is more than SGA Size) where is
> my uncommited data, if it is not in SGA and LOG Files or UNDO.
>
> (these are just assumptions)

Why do you think it is not in the logs? Have you ever noticed how much redo is generated when you insert lots of data? How big are those redo logs, 10M? What do you see with logminer? Oracle optimistically assumes you will be committing - ever do an imp and watch free space? - so has been flushing out some modified data buffers to disk at its leisure, depending on what else has been happening in the SGA. The undo just needs a rowid to delete it in case it is rolled back, whether 10M is going to be enough for that depends quite a bit on what you are doing, such as are there indices, and what everyone else is doing. When you recover, Oracle needs to rollforward, then rollback uncommitted transactions. Since you have switched redo 15 times and don't have archived logs, you will lose data and be unable to recover it should the database crash. That's what all those other comments about losing your job are about.

Don't assume. Test. Observe. Learn.

jg

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