Re: Onconfig Question

Barry asks: >I sent this a few weeks ago and didn't get any responses. I am >rephrasing the heading and trying again. One reason you might not hear back a lot on this topic is because consultants get about US$2,000 per day to answer this kind of thing. It's not in their best interest to go into detail for free here. [...] >Currently we have approximately 80 users with access to the database, >but typically we have at most 15 queries running at any given time. >Occasionally we may get as many as 25 queries peak. > >These are some of our onconfig settings: > >SHMVIRTSIZE 170000 >SHMADD 30416 >SHMTOTAL 0>PDQPRIORITY 2 >MAX_PDQPRIORITY 100 >DS_MAX_QUERIES 20 >DS_TOTAL_MEMORY 160000 >DS_MAX_SCANS 100> >PSORT_NPROCS is not set. > >1. Given everything above, how would you configure these parameters? >2. In the near future, DSS queries is likely to double or triple, >would you set the parameters differently? > >I am particularly interested in your opionions relating to decision >support variables and the best way to set PSORT_NPROCS variable. Given that this is a DSS system with many concurrent users, I would consider setting MAX_PDQPRIORITY to a value much less than 100. This would allow more than one DSS query to take advantage of PDQ at a time. Also, consider setting DS_MAX_QUERIES to match the number of queries that you'll have running at the same time. Tune these in conjunction with PDQPRIORITY to satisfy your user's requests. The command 'onstat -g mgm' is the tool to monitor these parameters. Using it you will be able to see where users are waiting for resources, and which resources those are. To learn more about these variables and how they can affect your processing, consider taking the 'Performance Tuning' class. Also, see the book "Informix-OnLine Performance Tuning" by Liz Suto, and the ubiquitous "Performance Guide" of TFM. Mostly, though, it is a long and tedious process of monitoring and tuning. Enjoy! _____________________________________________________________ Clem Akins (aka clem@informix.com) Informix Software, Inc (Standard disclaimers apply) International Technical Support Last seen: Motorcycling through shady redwood groves near SF