Hi all, my set of rules (100 files, 20 rules/file) was taking 30 seconds to compile until yesterday. Now I upgraded DRools to 5.1.1 and it takes about 2 minutes to compile. I'm on Windows XP and cannot notice any memory or CPU bottlenecks. I'm using an Ant task to do it, and the timing is exactly the same whether I'm using the DRools Ant compiler task, or I define a compiler task of my own. I can see in my own compiler task that this particular line is spending a few seconds per DRL file: builder.add( res, ResourceType.DRL ); so the effective compilation is the culprit right? I tried also to merge all the DRL files and compile them all-at-once but this didn't change anything. Do you have any idea what might have changed between 5.0 and 5.1 or what I could do to have it like before? Or even faster, of course :) Thanks a lot, JC