Sandeep Mishra, April 05, 2016 - 10:44 am UTC
Hi Connor,
Thank You.
SO can I conclude, I should consider controlfile autobackup when the scenario is as below.
+ I did a structural change,
+ and this change does not involve system tablespace
+ I want to take backup, after the change
+ and I am not backing up system tablespace
+ and I also want to backup the controlfile as well
Because other than the above typical scenario, I will always be taking db level backups [complete + incremental] so the system tablespace will always be included, resulting the controlfile backup taken, by default.
Thanks and Regards,
Sandep
April 05, 2016 - 12:05 pm UTC
That pretty much sums it up, but I like auto-backup because, (for example) if I add a datafile, I know my controlfile (which has just been altered) has been backed up.
Sandeep Mishra, April 06, 2016 - 7:24 am UTC
Hi Cononr,
Thank You.
Just one more query, apologies if it is bit different than the subject. Once I was asked, when the db is up and running, a file system backup is taken, i.e. backup of the all the mount points, through some OS utility. If the backup is deployed again will the db will be opening up. To my knowledge, I am sure it will go till mount mode, but not confident that it will go to open mode as well. My doubt is a datafile is copied first and then the archives, in this case the SCN is the header and logs will be different, the log which is copied later will have a higher scn, since the db is already up and running.
Just happen to see an article by TOM, where he is saying about retirement, but I would love to have the same website name maintained "Ask Tom". A Salute to TOM.
Thanks and Regards,
Sandeep
April 07, 2016 - 1:21 am UTC
Unless you have issued:
alter database begin backup
before you copied the files, and
alter database end backup
afterwards, then there is not a guarantee that you will be able to use the files that were backed up to get a running database. The 'begin backup' command is essential to let us know to save off a little more metadata in the redo logs to ensure that when the files are restored, we can sort out any inconsistencies like the ones you mention.
Sandeep Mishra, April 08, 2016 - 5:38 am UTC
Thank You.
I totally in agreement.
The confident of the questioning individual (a very senior DBA), forced me to rethink, so I asked.
Another reason of asking is may be it is possible just like another of the claims, many time senior DBAs are stating
"It is possible to increase the size of online redo log file, just like you increase a datafile size", though I have not yet found that command as of now. Still searching.
And, you need not answer, as this is not a question to you, just was curious, because most of the time I heard "There are many things possible, which are not documented or suggested by oracle", so just wandering, what else cracks are out there, been found out by senior DBAs
Regards,
Sandeep