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May 4th

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Connor McDonald

Thanks for the question, Gaddam.

Asked: November 22, 2016 - 6:21 am UTC

Last updated: November 25, 2016 - 7:57 am UTC

Version: 9i

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You Asked

Hi Tom,

Please clarify on below queries.

1. if database is in Hot backup mode (between 2:00 AM to 4:00 AM), the parallel tx at that time will be written to archive logs.
And once the hot backup mode finished these logs will be applied to db automatically. (is it correct).
2. If we loss any archive logs which were generated between 2 to 4:00AM then db will not in consistent state.

3. If db is in RMAN Inc0 backup mode (between 2:00 AM to 4:00 AM), the parallel tx at that time will be written to archive logs and it will also applied on db files. Once Inc0 backup finish, these generated logs will be applied on database or not.?
i know these archive logs required when we want perform recovery.

and Connor said...

1. if database is in Hot backup mode (between 2:00 AM to 4:00 AM), the parallel tx at that time will be written to archive logs.

Changes are always written to redo logs, and when they are full, the transferred to the archive logs (assuming the database is in archivelog mode). Whether hot back mode is active or not does not change that. Changes to datafiles still occur as per normal.

2. If we loss any archive logs which were generated between 2 to 4:00AM then db will not in consistent state.

No that is not correct. You need archivelogs to roll forward - so obviously you never want to lose them, but removing them does not impact a running database.

3) If db is in RMAN Inc0 backup mod

RMAN does not put the database into hot backup mode, because it is controlling the file copy to disk, so it is "smart" enough to detect ongoing changes whilst copying.

But in all cases, we dont "stop" writing to the database files during a backup.

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Comments

Thanks a lot for quick response

Gaddam Ramakrishna, November 24, 2016 - 7:38 am UTC

Thank you Connor..

I have oracle9i database on AIX 5.3 with archive mode. But all archive logs are compressing automatically the minute it get generated with Perl scripting. (file extn is .Z)
in this case can i take RMAN Inc0 backup or not. Because after finishing INC0 backup, databse will check for old archive logs or not.

Connor McDonald
November 25, 2016 - 7:57 am UTC

"But all archive logs are compressing automatically the minute it get generated with Perl scripting"

That sounds like trouble ahead :-)

(In my view) if you are using RMAN, then you really need to let RMAN take care of the archivelogs. If space is a problem, then you can run RMAN more frequently to *just* do the archivelogs and delete them once backed up.

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