Lock Contention Mystery

4GL/IDS Gurus: We're currently running an on-line 4GL 6.01 application to maintain Item Information such as description, cost, retail, store authorization on an IDS 7.20 running on HP-UX 10.10 (HP K400 machine). During the night and on weekends we run several *concurrent* UNLOAD (DBACCESS) batch jobs to keep our Mainframe legacy systems syncronized with all newly updated information. Occasionally, our UNLOAD processes fail due to locking contention issues. Since there are no users on the system during the run time of the unload processes, we believe that it is the UNLOAD processes themselves that are creating the locking issues. However, since the UNLOADs are merely selects that shouldn't be creating any application related locks we're a bit confused about where the locking problem stems from. Is it possible that we're actually experiencing an issue with a system table being EXCLUSIVELY locked as part of the UNLOAD process. we've increased the LOCK WAIT of the UNLOAD processes from zero to two minutes, which may help. However, since we never thought that SELECTs/UNLOADs created DB locks, so we don't understand why the LOCK WAIT should be necessary. Any help would be appreciated. Thanks for your time! BTW: All of the UNLOAD process run at ISOLATION LEVEL DIRTY READ. David Murray. Albany, NY