Oracle7 Administrator's Reference for UNIX
Using Trace and Alert Files
This section describes the trace (or dump) files the Oracle Server creates to diagnose and resolve operating problems.
Trace File Contents
Oracle7 creates trace files for exceptions; it associates each trace file with the process for a particular instance. If it encounters an exception, such as an access violation or an attempt to divide a value by 0, Oracle7 writes a trace file. Detached processes and servers also create trace files. Oracle7 records regular operations in the alert file, not in additional trace files. You rarely use these files, although you may need to send a trace file to your Oracle Worldwide Technical Support representative for analysis.
A trace file contains:
- dumps of the SGA, Process Global Area (PGA), and supervisor stacks
Trace File Names
The format of a trace file name is processname_sid_unixpid.trc
where:
| processname | is a three- or four-character process name showing which Oracle7 process the trace file is from (for example, PMON, DBWR, ORA, or RECO) |
| sid | is the instance system identifier |
| unixpid | is the UNIX process ID number |
| .trc | is a file name extension appended to all trace file names |
A sample trace file name is lgwr_TEST_1237.trc.
Note: If your system does not support filenames longer than 14 characters, the syntax of a trace file name is processname_unixpid.trc.
Specifying Trace File Directories
There are two types of trace files:
- trace files created by Oracle7 detached processes
- trace files created by user processes
Trace file information is only required for specific problem analysis. Remove the files periodically to avoid excessive disk space usage.
The following three initialization parameters define the directories where trace files are sent:
| BACKGROUND_DUMP_DEST | is the directory where dump files created by detached processes and alert files are sent. |
| USER_DUMP_DEST | is the directory where dump files created by user processes are sent. |
| CORE_DUMP_DEST | is the directory where dump files created by core dumps are sent. |
Alert Files
The alert_sid.log file is associated with a database and is located in the directory specified by the initsid.ora parameter BACKGROUND_DUMP_DEST. The default value is $ORACLE_HOME/rdbms/log. This file logs more information than the usual trace files, including the following unusual database occurrences:
- instance startup and shutdown
- messages to the operator console
- errors that cause a trace file to be created
- any CREATE, ALTER, or DROP operations issued on a database, tablespace, or rollback segment
- initsid.ora parameters current to the instance
- background processes being spawned
- log switches and checkpoints
Attention: Administer this file as you would other trace files. Because each new entry to this file is appended to the file, you should clear it periodically.