如果在一个session下面，使用多次命令alter database backup controlfile to trace，则会追加到一个同样的文件里面
如果在不同的session，也就是不同的会话窗口，则会新建一个以.trc为后缀的文件。
测试：
在第一个窗口：
SQL> alter database backup controlfile to trace;
Database altered.
SQL> select d.value||b.bias||lower(rtrim(i.instance, chr(0)))||'_ora_'||p.spid||'.trc' trace_file_name from ( select p.spid from sys.v$mystat m,sys.v$session s,sys.v$process p where m.statistic# = 1 and s.sid = m.sid and p.addr = s.paddr) p, ( select t.instance from sys.v$thread t,sys.v$parameter v where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i, ( select value from sys.v$parameter where name = 'user_dump_dest') d,(select DECODE(count(BANNER),0,'/','\') bias from v$version where upper(banner) like '%WINDOWS%') b;
TRACE_FILE_NAME
----------------------------------------------------------------------------------------------------
/u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_1859.trc
SQL> alter database backup controlfile to trace;
Database altered.
SQL> select d.value||b.bias||lower(rtrim(i.instance, chr(0)))||'_ora_'||p.spid||'.trc' trace_file_name from ( select p.spid from sys.v$mystat m,sys.v$session s,sys.v$process p where m.statistic# = 1 and s.sid = m.sid and p.addr = s.paddr) p, ( select t.instance from sys.v$thread t,sys.v$parameter v where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i, ( select value from sys.v$parameter where name = 'user_dump_dest') d,(select DECODE(count(BANNER),0,'/','\') bias from v$version where upper(banner) like '%WINDOWS%') b;
TRACE_FILE_NAME
----------------------------------------------------------------------------------------------------
/u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_1859.trc
另开一个窗口：
SQL> alter database backup controlfile to trace;
Database altered.
SQL> select d.value||b.bias||lower(rtrim(i.instance, chr(0)))||'_ora_'||p.spid||'.trc' trace_file_name from ( select p.spid from sys.v$mystat m,sys.v$session s,sys.v$process p where m.statistic# = 1 and s.sid = m.sid and p.addr = s.paddr) p, ( select t.instance from sys.v$thread t,sys.v$parameter v where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i, ( select value from sys.v$parameter where name = 'user_dump_dest') d,(select DECODE(count(BANNER),0,'/','\') bias from v$version where upper(banner) like '%WINDOWS%') b;
TRACE_FILE_NAME
--------------------------------------------------------------------------------
/u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_3426.trc