On Feb 19, 2009, at 7:12 PM, Lars Ermert wrote:
I would be also very grateful if you could give me any suggestions on how to optimize the engine for constant running,if necessary or possible.
I can't give you any concrete explanation as to what's going wrong here; this still isn't enough information. But the path to an answer is the same as it would be if Jess were not involved, the same as for any software performance issue: do some profiling, and see what's going on. You can use Jess's built-in tools -- for example, the "watch" command -- to find out exactly what rules are firing, and/or what facts are being asserted; since the performance characteristics don't make sense, you'll likely be surprised by these results. Use "watch", pipe the results into a file, then examine the file.
Given that memory use is not increasing without bound, and the CPU is being pegged, I'm guessing you've just got some simple rule loops -- a rule unexepectedly reactivates after one of its conditions is modified, or one rule activates a second, which upon firing reactivates the first, in a cycle. Jess's "no-loop" and "slot- specific" features can help resolve these. Either of these will be very obvious in "watch" output.
Besides Jess's own built-in tools, you can use a regular Java profiler. This will be a little trickier, but it will still (if you've got a source license, anyway) give you an indication of where all the time is going.
--------------------------------------------------------- Ernest Friedman-Hill Informatics & Decision Sciences Phone: (925) 294-2154 Sandia National Labs PO Box 969, MS 9012 [email protected] Livermore, CA 94550 http://www.jessrules.com -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users [email protected]' in the BODY of a message to [email protected], NOT to the list (use your own address!) List problems? Notify [email protected]. --------------------------------------------------------------------
