Re: Archive log files reaches maxloghistory

Brian Peasland <dba_at_remove_spam.peasland.com> writes:

> You will find that the CONTROL_FILE_RECORD_KEEP_TIME is more of a
> driver than MAXLOGHISTORY. For instance, C_F_R_K_T defaults to 7
> days. Let's assume that you have MAXLOGHISTORY set to 1,000. What
> happens if you generate more than 1,000 logs in those 7 days? The
> control file will automatically expand and then the value for
> MAXLOGHISTORY will be increased. Eventually, the 7th day has been
> reached and the records will be overwritten in the control file. It
> was a couple of years ago that I did some experiments and posted the
> results to this very newsgroup.

Very interesting but if I understand the OP quite right then he asked: is the creation parameter MAXLOGHISTORY very *important* for database that are in ARCHIVELOGMODE or in other words has this parameter an influence in the recovery process. From reading it seems to me that the log history records are only for informational purposes. If the limit is reached then the records are reused. But I am not quite sure.

> On Friday 24 October 2003 18:42, Peter thoughtfully contributed:
>
>> What happens if the number of archive log files reaches the number
>> equal to MAXLOGHISTORY? The control does not have enough space to
>> hold information of any additional archive log files. Is it now
>> safe to delete some of the older archive log fles.

Here I would say it is *not safe to* delete them. Especially if you restore a data file that points to a SCN that is recorded in one of the deleted log files. In that case you *cannot* recover the database to the current point and you have to cancel the recover process with all the consequences. As far as I understand.

Harald Received on Sun Oct 26 2003 - 00:16:50 CDT