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jok llamera


hi fellas,

Im sure one of you here is an Oracle DBA, Im using HPUX 11.0 and I have a question when writing a data from redolog(RAW) to the archivelog files(Filesystem). Does it bypasses the oracle buffer cache or not?

Excelence is not an act but a hobby
Carlos Fernandez Riera
Honored Contributor

Re: archiver

And the answer is NO.

You can check it with tusc:

tusc -f -o /tmp/tusc.log -a -s open,read,write -p PID

PID is PID of ora_arch_$ORACLE_SID

It seem to open redolog file for read only, open a new redolog_on_disk file and write while read.

Andreas D. Skjervold
Honored Contributor

Re: archiver


The archiver will use the Redo Log Buffer.

The archiver will:
1) read the control file to find any unarchived logs,
2) open online redo log members to be read,
3) allocate redo log buffers,
4) read the online redo log,
5) fill redo log buffers,
6) write to the archive files,
7) update control file with new information,
8) starts the loop again.

Only by ignoring what everyone think is important, can you be aware of what everyone ignores!
Ryan Kogelheide
Frequent Advisor

Re: archiver


That's interesting. I've obviously misunderstood something about how the archiver works.

What I always imagined is that it would read and edit the control file while doing a simple OS copy.

Why does it need to work with redo buffers?