how release threads?

dear all we have an java application running on websphere 5 and using jdbc connection pooling accessing data in IDS 9.40.FC3 on AIX 5.2, pdqpriority=1 there is 20 connections-user session used by appserver and reused within connection pooling by many users however, the number of associated threads increases from day to day, currently more than 3000 it seems every session holds its threads even not used anymore onstat -g ath looks like, e.g.:98365 7000000a8df0e00 7000000ae4537a0 2 cond wait await_MC34 4cpu scan_34.0 which means scan threads waiting for condition await_MC34 onstat -g con shows, e.g. 4787 7000000ac345418 await_MC34 98372 86898 what are these threads waiting for? how to release them? why it is not release automatically? what is await_MC?? thank you regards rasto sending to informix-list