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Diagnostic Sources. Objectives. After completing this lesson, you should be able to do the following: Use various files for diagnostic purposes Alert Log Trace files Core files System logs Use Enterprise Manager to view alerts Adjust thresholds for tracked metrics

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Presentation Transcript

Objectives
Objectives

  • After completing this lesson, you should be able to do the following:

    • Use various files for diagnostic purposes

      • Alert Log

      • Trace files

      • Core files

      • System logs

    • Use Enterprise Manager to view alerts

    • Adjust thresholds for tracked metrics

    • Control the size and location of trace files


Diagnostic files
Diagnostic Files

  • The alert.log file

  • Trace files

  • Core dump files

  • System log files


The alert log
The Alert Log

  • The Alert Log contains:

    • All internal errors

    • Administrative operations, such as CREATE, ALTER, and DROP statements

    • Shared server errors

    • Materialized view refresh errors

    • Initialization parameter values


What is in the alert log file
What Is in the alert.log File

  • Every instance generates a file called alert.log, which logs the following information:

    • Diagnostic data from background and foreground processes

    • Summary information regarding errors and pointers to trace files for detailed information

    • Information since database creation (unless purged) that might be useful in backtracking a problem



Alert models architecture
Alert Models Architecture

Subscribingclients

Serveralerts

EMalerts

Thirdparty

EM Console

AutomaticPushedNotification

EMD

Pollstatistics

Datadictionary

Serveralertsqueue

Server monitors itself

Oracle database(SGA)

AWR

MMON


Server generated alert types
Server-Generated Alert Types

Metric-based

97% Critical

Cleared

Threshold(stateful)alerts

85% Warning

Cleared

MMON

DBA_OUTSTANDING_ALERTS

DBA_ALERT_HISTORY

Recovery Area Low On Free Space

ResumableSessionSuspended

SnapshotToo Old

Nonthreshold (stateless)alerts

Alert

Event-based








Trace files
Trace Files

  • Every server process, on encountering an exception, writes diagnostic data to a trace file

  • The trace file header contains the following information:

    • OS and version

    • Oracle version and options installed

    • Instance name

    • Process ID


Specifying the location of trace files
Specifying the Location of Trace Files

  • Initialization parameters controlling the location and size of trace files include:

    • BACKGROUND_DUMP_DEST

    • USER_DUMP_DEST

    • MAX_DUMP_FILE_SIZE


Controlling trace file size
Controlling Trace File Size

  • Using Enterprise Manager


Controlling trace file writes
Controlling Trace File Writes

  • Trace files are usually generated by a server process upon encountering an error.

  • Some background processes like ARCn, have parameters that control the amount and type of trace information generated.

  • In some instances, trace files can be generated for server processes at user request.

SQL> ALTER SESSION SET SQL_TRACE TRUE;


Using enterprise manager to enable and view sql tracing
Using Enterprise Manager to Enable and View SQL Tracing

SQL> SELECT * FROM dba_enabled_traces;


System log files
System Log Files

  • System log files capture error messages and exceptions encountered at the OS level

  • These would be useful if a hardware or OS problem is suspected


Summary
Summary

  • In this lesson, you should have learned how to:

    • Use various files for diagnostic purposes

      • Alert Log

      • Trace files

      • Core files

      • System logs

    • Use Enterprise Manager to view alerts

    • Adjust thresholds for tracked metrics

    • Control the size and location of trace files


Practice 7 overview diagnosing problems
Practice 7 Overview: Diagnosing Problems

  • These practices cover the following topics:

    • Setup server-generated alerts

    • Monitor server-generated alerts


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