14.3. System Trace Files

An Oracle instance's system trace files are stored in the same directory as the alert log file, in the directory specified by the system parameter BACKGROUND_ DUMP_DEST. The system trace files contain debugging, status, and error messages for each of the background processes, such as SMON, PMON, DBWx, LGWR, and so forth.

system trace file

A text file that pertains to a single background process and contains status, debugging, or error information about that background process. System trace files are stored in the directory specified by the system parameter BACKGROUND_ DUMP_DEST.

Janice, the DBA, notices that there are quite a few system trace files in the BACKGROUND_DUMP_DEST directory:

[oracle@oltp bdump]$ ls -l
total 44888
-rw-r--r--  1 oracle   oinstall   4006 Jun 22 22:23
alert_ord_2004-06-21.log
-rw-r--r--  1 oracle   oinstall  26010 Jun 23 19:40
alert_ord.log

-rw-r-----  1 oracle   oinstall     691 May 18 07:00
ord_arc0_10663.trc
-rw-r-----  1 oracle   oinstall     693 Mar 14 12:53
ord_arc0_11830.trc
. . .
-rw-r-----  1 oracle   oinstall     688 May 30 11:23
ord_arc1_3306.trc
-rw-r-----  1 oracle   oinstall     772 Mar 28 13:02
ord_arc1_3369.trc
-rw-r-----  1 oracle   oinstall     690 Mar 19 07:51
ord_arc1_3505.trc
. . .
-rw-r-----  1 oracle   oinstall     685 Mar 20 09:54
ord_dbw0_6181.trc
-rw-r-----  1 oracle   oinstall    3820 Mar 14 12:17
ord_dbw0_6399.trc
-rw-r-----  1 oracle   oinstall    1352 Mar 14 12:29
ord_dbw0_9796.trc
-rw-r-----  1 oracle   oinstall     850 Mar 14 12:55
ord_j000_11844.trc
-rw-r-----  1 oracle   oinstall     852 Mar 14 13:15
ord_j000_14335.trc
-rw-r-----  1 oracle   oinstall     859 Mar 14 13:15
ord_lgwr_12043.trc
[oracle@oltp bdump]$

She sees quite a few files for the DBW0 (database writer) background process, so she is concerned that there might be a problem with DBW0. She opens one of the DBW0 trace files, ord_dbw0_6181.trc, to see what the problem might be.

She looks at the contents of the file and realizes that most processes, including DBW0, generate a trace file at database startup. As a result, the trace file is merely informational in this case, and there appears to be nothing wrong with DBW0.