Why do you want to use parallelism? If it is for performance reasons, you need to prove that parallelism would help not hurt. Doug Burns has done extensive research into parallelism (http://oracledoug.com/papers.html) and I strongly recommend reading it.
In terms of the actual wait events, you will need to trace the parallel slave sessions and use trcsess to combine the trace files so you can profile them.
Regards, Daniel Fink -- Daniel Fink Oracle Performance, Diagnosis, Data Recovery and Training OptimalDBA http://www.optimaldba.com Oracle Blog http://optimaldba.blogspot.com Lost Data? http://www.ora600.nl/introduction.htm -- //www.freelists.org/webpage/oracle-l
