Trace File are trace (or dump) file that Oracle Database creates to help you diagnose and resolve operating problems.
Each server and background process writes to a trace file. When a process detects an internal error, it writes information about the error to its trace file.
The file name format of a trace file is sid_processname_unixpid.trc, where:
The following is a sample trace file name:
$ORACLE_BASE/diag/rdbms/mydb/mydb/trace/test_lgwr_1237.trc
where ORACLE_BASE is the Oracle Base Directory
To see a formatted display of a SQL Trace file, drag the *.trc file onto the area above the SQL Worksheet (or open it by clicking File, then Open).
Set the MAX_DUMP_FILE initialization parameter to at least 5000, to ensure that the trace file is large enough to store error information.