Database Reference
In-Depth Information
log an error in the alert log of the database. Here is an example of an error you might see in
the alert log (we discuss finding the alert log of the database later in this chapter):
All online logs needed archiving
ARCH: Archival stopped, error occurred. Will continue retrying
ORA-16014: log 2 sequence# 29 not archived, no available destinations
ORA-00312: online log 2 thread 1: 'C:\ORACLE\ORADATA\ORCL\REDO02.LOG'
Also, users logging into the database will find their logins just hanging until the archive-
log problems are solved.
We've covered the parameters needed to put the database in ARCHIVELOG mode and
the basic steps involved in the process. Let's look at an example of actually putting the
database in ARCHIVELOG mode. Exercise 1.1 provides an example of doing just that.
Online Redo logs Stop Being Archived
We can't tell you how many times this has happened to us as DBAs. You are busy design-
ing some cool model and the operations guys call. “Hey,” they say, “we are getting calls.
The database isn't working anymore.”
“What?” you respond. “What do you mean it's not working?”
“The user sessions are just stalled, sitting there not doing anything. It's like the database
has gone out to lunch or something,” the operations guy says.
Immediately you are pretty sure you know what's wrong. So you ask the operations
guy, “So, the mount point for the archived redo logs. Are you possibly getting an alert
that it's full?”
The operations guy fumbles around to look at the alerts. Sure enough, the archived redo
log destination is filled up. “Oh, yeah … I was going to call you about that but I forgot.”
So, you proceed to back up the archived redo logs and then remove them from the system
to free up space. You also follow up to make sure some additional disk space is added to
the file system.
This kind of situation happens a lot if you do not have enough space available for your
archived redo logs or if your backups stop working. I've seen this happen frequently in
shops where the database was originally designed for a certain amount of use and that
usage has increased significantly
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