November 1999
Intermediate to advanced
736 pages
22h 46m
English
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A Broken Record
There are some common threads that appear throughout this chapter. Here they are once again:
- Mirror the redologs
If all members (or the only member) of an ACTIVE or CURRENT log group are lost, there will be data loss. If the redologs are not mirrored, the chances of this happening are much greater than if the redologs are mirrored. If the redologs are mirrored, the chance that all members of a log group would be damaged is incredibly small. A little research and a little effort up-front will significantly reduce the chances of data loss.
- Watch the alert log
Even if the redologs are mirrored, one or more members of a log group may be damaged while the database is operating. The only notification will be an entry in the alert log. Automate the checking of the alert logs for error messages. Otherwise, there may be only one functioning member of a log group, and you may not even know it.
- Mirror the control files
A significant portion of this recovery procedure is dedicated to recovering from the loss of all control files. If they are not mirrored, they should be— another example that Prior Proper Planning Purges the Person from the Performance of Painful Procedures.
- Use ARCHIVELOG mode
Without ARCHIVELOG mode, Steps 23 and 24 could replace the entire recovery procedure. If one datafile is lost, restore all of them and open the database with the resetlogs option. All changes since the last cold backup will be lost, and a cold backup is the only kind of backup possible, ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.