Beginning Oracle Database 11g Administration From Novice to Professional

CHAPTER 11 FIXING PROBLEMS 253
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by a hyphen. The DBA must learn to identify which Oracle error codes
indicate problems with the database infrastructure and which codes indicate
errors made by a user or a problem with an application. The named exceptions
defined by PL/SQL are examples of error codes that indicate problems in the
application, not in the database infrastructure.
error message means that the query has taken so
long that the undo information required to re- create the required read- consistent
snapshot of the database has been overwritten by other transactions—that is, the
snapshot is too old to be reconstructed.
error message means that Oracle detected that
two transactions are blocking each other and picked one of them as a victim. The
appropriate action that the victim must take is to issue the command and
retry its transaction.
error message indicates that Oracle encountered
an unexpected condition and stopped processing the query in question.
ORA- 00600 errors should always be investigated, and the DBA should confirm that
they were not triggered by corrupted data blocks.
error message means that the Oracle server
process attempted to perform an illegal operation and was forced to terminate
itself by the operating system.
Exercises
in this chapter. Use any of the resources listed in this chapter to determine the
root cause of the problem and find the permanent fix.
messages are recorded in the alert log. Check whether a trace file is produced and
review it. What happens if the victim simply retries its last SQL command instead
of issuing the command and retrying its entire transaction?
session B, but Oracle cannot take any action because this is not yet a deadlock
scenario. Use a GUI tool such as SQL Developer, Enterprise Manager, Toad, or
DBArtisan to identify the blocking process and terminate it.