Oracle Alert and Trace Files

Objectives

	After completing this lesson, you should be able to
	do the following:
	Describe the location and usefulness of the Alert log file
	Describe the location and usefulness of the background and user process trace files

Diagnostic Information

	Trace files:
	Alert log file
	Background process trace files
	User trace files

Alert Log File

	The Alert log file consists of a chronological log of messages and errors.
	Check the Alert log file regularly to:
		Detect internal errors (ORA-600) and block corruption errors
		Monitor database operations
		View the nondefault initialization parameters
	Remove or trim the Alert log file regularly after checking.

Controlling the Alert Log File

Background Processes Trace Files

	The Oracle server dumps information about errors detected by any background process in trace files.
	Oracle support uses these trace files to diagnose and troubleshoot problems.

Controlling the Background Processes Trace Files

User Trace Files

	Server process tracing is enabled or disabled at the session or instance level by:
		The ALTER SESSION command
		The SET_SQL_TRACE_IN_SESSION procedure
		The initialization parameter SQL_TRACE
	A user trace file contains statistics for traced SQL statements for that session.
	A user trace file is useful for SQL tuning.
	The Oracle database creates user trace files on a per-server-process basis.

Controlling the User Trace Files

Summary

	In this lesson, you should have learned how to:
	Set, retrieve, and use the Alert log file
	Use background processes trace files
	Trace user SQL statements