Re: RESIDENT and PDQ

> > Art S. Kagel wrote in message <36F6C3A9.5B3C@bloomberg.net>... > > >BTW 7.30 added other values for RESIDENT to lock the > >Virtual segments as well. > > > >Art S. Kagel > > > Does this suggest that it is possible to cache up and make resident light > scan reads? > > We have a relatively small, but not totally uncommon data warehouse whose > total size is <2G. We would like to use PDQ 100 for intensive DSS queries > to get parallel execution, but then light scans would ignore entire tables > cached in LRQ buffers (from previous operations), preferring instead to do > new physical read from disk, right? Light scans are great, but wouldn't it > be much, much faster if PDQ could read from buffers, instead of disk, WHEN > COMPLETE TABLES ARE ALREADY RESIDENT IN BUFFERS? >From the Peformance Guide, version 7.3, pg. 3-59: "System catalog tables and tables smaller than the size of the buffer pool do not use light scans." Thus, if the complete tables are already in LRU buffers, they are not eligible for light scans. Mark Collins mcollins@us.dhl.com