How to find the Trace file generated for a concurrent program

You can use the following query to locate the trace file, it takes as input the ' Concurrent Request id'

SELECT
'Request id: '||request_id ,
'Trace id: '||oracle_Process_id,
'Trace Flag: '||req.enable_trace,
'Trace Name: '||dest.value||'/'||lower(dbnm.value)||'_ora_'||oracle_process_id||'.trc',
'File Name: '||execname.execution_file_name|| execname.subroutine_name ,
'Status : '||decode(phase_code,'R','Running') ||'-'||decode(status_code,'R','Normal'),
'SID Serial: '||ses.sid||','|| ses.serial#, 'Module : '||ses.module
from
fnd_concurrent_requests req,
v$session ses,
v$process proc,
v$parameter dest,
v$parameter dbnm,
fnd_concurrent_programs_vl prog,
fnd_executables execname where req.request_id = &request
and req.oracle_process_id=proc.spid(+)
and proc.addr = ses.paddr(+)
and dest.name='user_dump_dest'
and dbnm.name='db_name'
and req.concurrent_program_id = prog.concurrent_program_id
and req.program_application_id = prog.application_id
and prog.application_id = execname.application_id
and prog.executable_id=execname.executable_id;

The output would be 'directory'/'filename.trc'
eg: 'directory'/ora_3465_act.trc.

In the above directory, do 'ls -l' for '*3465*trc' and any latest file that you see with 3465 as a part of the file name would be the trace file.