Re: System tuning

This is a multi-part message in MIME format. --------------45AFA295EB9 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Informix Sysadmin wrote: > MULTIPROCESSOR 1 > NUMCPUVPS 2 > SINGLE_CPU_VP 0 As someone else has already pointed out, on a 2-proc box, you may find better performance is achieved by tuning OnLine as though it were on a uniprocessor. This is especially true if the box is not dedicated to being a database server. > NUMAIOVPS The default value for NUMAIOVPS is 2*chunks, if I recall. That may be more than you need, esp. if a chunk <> disk. More don't usually hurt performance, as they just wind up idle and swapped out. > CKPTINTVL 300 I'd say this is low, but if you had not been seing problems with it before, you shouldn't now. > RA_PAGES > RA_THRESHOLD If you are doing a fair amount of read i/o, you probably want to set these. The default values are quite low (like 4 or 8, I forget offhand). Set these at maybe 64 and 32, and it should help for i/o heavy activity. > PDQPRIORITY 0 If you have fragmented your tables at all, you may want this at 1 at least; that will give you parallel scans. Even on a uni or 2 proc system, parallel scans can be a win. > OPTCOMPIND 1 Be sure that your index accesses are truly faster. In some cases, a hash join may be the better choice. It is at least worth a few tests to be certain. -- Dave Kosenko, Informix Professional Services **************************************************************************** While it is true that there is more than one way to skin a cat, the cat himself generally fails to appreciate the differences. --------------45AFA295EB9 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="IFXDISCL.TXT" ************************************************************************* Note: please do not send me email asking about features, or asking about Informix problems and how to solve them. I answer what questions I can in this forum (comp.databases.informix) when I have the time to spare. For questions on features, call your local sales rep or check out the Informix web site (http://www.informix.com). For technical problems, call Informix tech support. ************************************************************************* Disclaimer: All opinions expressed in this message are well-reasoned and insightful; needless to say, they are not those of Informix Software, its partners or lackeys. Anyone who says otherwise is itching for a fight. --------------45AFA295EB9--