We used Drools as part of a solution to act as a sort of filter in a very intense processing application, maybe running up to 100 rules on 500,000 + working memory objects. turns out that it is extremely slow. anybody else have any experience using Drools in a batch type processing application?
I haven't worked with the latest version of Drools (last time I used it was about a year ago), but back then our high-load benchmarks proved it to be utterly slow. A huge disappointment after having based much of our architecture on it.
At least something good I remember about drools is that their dev team was available on IRC and very helpful, you might give them a try, they're the experts after all: irc.codehaus.org #drools