Re: Lock Contention Mystery

QueriX 4GL / Mehdi wrote: > David Murray wrote: > > > 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 > > You may try running UPDATE STATISTICS before your unload process starts to see > if this helps. You can also run oncheck. > I mean onstat. Compliments of QueriX -------------------------------------------------------------------------------------------------- QueriX 4GL Compilers are Informix 4GL Compatible, and Connection to other RDBMS such as Oracle. Hydra 4GL Compiler (Compatible with I4GL) Compile once, run everywhere Phoenix Windows GUI. (Front End to 4GL) Chimera Java GUI The only GUI you will ever need... (Front End to 4GL) Arachne Web Technology (Front End to 4GL on the Web & HTML Report Generator) ESQL/C Compiler For more details visit: http://www.querix.com/ ---------------------------------------------------------------------------------------------------