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Re: Log Checkpoint

From: Eng. José Viegas <jose.viegas_at_onsite.pt>
Date: Tue, 2 Jan 2001 15:26:07 -0000
Message-ID: <92srje$ohr$1@venus.telepac.pt>

Hello and Happy New Year !!

I didn't understand your question... do you want to reduce the number of checkpoints or to
archive your logs ?

First of all, for the logs to be archived you must set the database to archive mode. If this is not true you'll never have any log archives.

The checkpoint is used by the database to write dirty blocks in memory to the datafiles. This means that if the database crashes, it will recover from the last checkpoint
done, which the reference exists in the control file, and in all database files.
For the database recover it must uses the log files, which contains all the transactions made to
the database, and the rollback segments to undo any uncompleted transactions.

When the log file is full, there is inevitably a checkpoint, because the use of log files is rotative, and
the database must garantee that the changes made are writen to the files.

As you can see, you can never eliminate completely the checkpoints.

Also there has been changes in the checkpoint parameters definitions in the 8i versions of Oracle.
If your Oracle Server is the Standard Edition, the LOG_CHECKPOINT_TIMEOUT has the minimum
value of 900 (15 min).
If your Server is the Enterprise Edition, you can also check for the FAST_START_IO_TARGET
to control your checkpoints.

In any case you can check the view V$INSTANCE_RECOVERY to determine which parameter
is controling your checkpoints.

Note that this is only for 8.1.x versions.

If you need for me to be more specific, just ask !

P.S. Sory for my bad English.

Jose Viegas
Oracle DBA



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<ccdicky_at_my-deja.com> wrote in message news:92repa$vc2$1_at_nnrp1.deja.com...
> Hi there,
>
> I am newbie of Oracle8i. I know the log will be archived out every one
> and half hour by default log checkpoint settings even though the log is
> not full. However, on my development site, due to the space
> constraint, I disable this default by following settings:
>
> log_checkpoint_timeout = 0
> log_checkpoint_interval = 0
>
> And everything remains default. I thought the log should have been
> archived out when the log is got full. But it is not. Can anybody
> tell me what is the right way to disable the log checkpoint. Any input
> would be appreaicated.
>
> Dicky
>
>
> Sent via Deja.com
> http://www.deja.com/
Received on Tue Jan 02 2001 - 09:26:07 CST

Original text of this message

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