Redo Log Files

[Sureshy]

Hi Friends

I have looked at the bytes column in V$LOG on a test instance and it states that my redo log files are 52MB each.

Looking at log_archive_dest, I can see that I have an archive log file in there at 189k, created 2 days ago

As far as I know the redo_log files have not changed since database creation 12 months ago.

can anyone explain ?

Thanks

[Halo]

This can happen if there was a manual switching of the redo log files or a log switch during hot backup.

[omegamark]

If the redo log fills it switches to the other redologs .That is the reason oracle has a minimum of 2 redo logs.The size of your archivelogs can vary from 52M to anywhere because that day you would have given alter system switch logfile ;

i do not know why you would have given that.At that time the
archive logs will be the size of the data's that are filled in the redo logs ...


Hope this helps ...

[Sureshy]

Hi Friends.

I have just remembered that the server crashed and was rebooted without shutting down the database.
The archive file is dated at exactly the same time and date as when the server was rebooted and the instance restarted.

Does this mean that Oracle archived the current redo log file and switched to the second one on startup, even though it had hardly any data in it ?

Does anyone know why ?

Thanks

Suresh

[jt]

How often does your redo log switch? 52M seems to be really large. In general for OLTP type of database the redo should switch about every 15 minutes. If yours does not even switch for over 2 days, you have a huge risk of loosing days of information in the redo in case there is a media failure.

[Sureshy]

Not really concerned about redo log size on this instance as it is test system.
Can anybody tell me how to shrink to about 10MB though.
I have three redo logs in 3 groups.

Thanks

Suresh

[pando]

you cannot resize redologs, you have to drop them and recreate them
if you are not very experienced resize the redologs with database in mount state (you can do it on fly just that you need to be more careful)

[Sureshy]

Hi Pando.

I am going to dop my existing members and create new ones.
At the moment I have three files in 3 groups.

group1 status = blank
group2 status = stale
group3 statis = blank

A blank status fleld usually means that the file is in use doesn't it, this means I cannot drop a group with a blank status?

Group2 is stale because the log was archived prematurely due to a memmory leak which forced me to reset my server without shutting down the instance. Can I drop group2 ?

Also.. If a blank status means that the file is in use then why are 2 of my redologfiles in use?

What are the correct status's which allow a logfile or group to be dropped ?

Thanks

Suresh

[Sureshy]

Sorry Pando, was looking at V$Logfile instead of V$Log.
I now have inactive and current status's.

Know wht to do from here.

Cheers
Suresh

[pando]

you want to do it on fly?