TRACEFILE_IDENTIFIER specifies a custom identifier that becomes part of the Oracle Trace file name. Such a custom identifier is used to identify a trace file simply from its name and without having to open it or view its contents.

Each time this parameter is dynamically modified, the next trace dump will be written to a trace file which has the new parameter value embedded in its name. Trace file continuity information is automatically added to both the old and new trace files to indicate that these trace files belong to the same process.

This parameter can only be used to change the name of the foreground process' trace file; the background processes continue to have their trace files named in the regular format. For foreground processes, the TRACEID column of the V$PROCESS view contains the current value of the TRACEFILE_IDENTIFIER parameter. When this parameter value is set, the trace file name has the following format:

sid_ora_pid_traceid.trc

In this example, sid is the oracle instance ID, pid is the process ID, and traceid is the value of the TRACEFILE_IDENTIFIER parameter.

实践：

SQL> alter session set sql_trace=true;

会话已更改。

SQL> alter session set tracefile_identifier='qin';

会话已更改。

结果：

D:\oracle\admin\qin\udump>dir
 驱动器 D 中的卷是 开发工作盘
 卷的序列号是 C88E-E197

 D:\oracle\admin\qin\udump 的目录

2009-04-16  16:34   

          .
2009-04-16  16:34              ..
2009-04-16  16:35               622 qin_ora_7440.trc
2009-04-16  16:47           212,516 qin_ora_748.trc
2009-04-16  16:49               944 qin_ora_9888.trc
2009-04-16  16:51               704 qin_ora_8696.trc
2009-04-16  16:52            16,267 qin_ora_7188.trc
2009-04-16  16:52               604 qin_ora_7360.trc
2009-04-16  16:54               639 qin_ora_3592.trc
2009-04-16  16:54               725 qin_ora_10024.trc
2009-04-16  17:19               639 qin_ora_7160.trc
2009-04-16  17:19               723 qin_ora_9676.trc
2009-04-16  17:37               640 qin_ora_8376.trc
2009-04-16  17:37               723 qin_ora_6084.trc
2009-04-17  07:46             1,344 qin_ora_3364.trc
2009-04-17  08:32             1,223 qin_ora_7548.trc
2009-04-17  08:33             1,994 qin_ora_7548_qin.trc
              15 个文件        240,307 字节
               2 个目录  2,382,249,984 可用字节

D:\oracle\admin\qin\udump>