Looks like you didn't specify the tracefiles in the command line when you call trcsess. List them : trcsess output=vvp.trc clientid=vvp42660 kiran_ora_4714776_vvp42660.trc kiran_ora_1638558_vvp42660.trc kiran_ora_4571498_vvp42660.trc kiran_ora_5574948_vvp42660.trc Cheers Stefan ========================= Stefan P Knecht CEO & Founder s@xxxxxxxx 10046 Consulting GmbH Schwarzackerstrasse 29 CH-8304 Wallisellen Switzerland Phone +41-(0)8400-10046 Cell +41 (0) 79 571 36 27 info@xxxxxxxx http://www.10046.ch ========================= On Wed, Aug 5, 2009 at 2:29 PM, Balakrishna Y <krishna000@xxxxxxxxx> wrote: > Hi all, > > I have below trace files in udump as > > kiran_ora_4714776_vvp42660.trc > kiran_ora_1638558_vvp42660.trc > kiran_ora_4571498_vvp42660.trc > kiran_ora_5574948_vvp42660.trc > > > I am trying to merge all this trace files using trcsess but this generates > 0 size output file. Dont really understand why ?? > > trcsess output=vvp.trc clientid=vvp42660 > > Regards > > Bala > > >