Re: [rules-users] calling function in When which one is faster

NO, I did NOT mistype. But I also wrote "probably". Your three alternatives aren't even exchangeable. For a serious discussion, provide a complete code example with true, exchangeable alternatives and then one might benchmark. The myth that eval is "the slowest of all possibilities" is due to imprecise statements from people not taking enough time to write. The truth is that constraints where indexing is possible are faster than anything else. Among the runners-up, it depends on the complexity of the inner workings, which depend on the CE type and may vary between versions. eval() is just a simple boolean expression, akin to any regular constraint where indexing does not apply. Whether JITting or some interpretation applies also depends on the Drools version and what not, so, once more: only benchmarking tells you hard facts. -W On 14/02/2014, wtang <wtang(a)kana.com&gt; wrote: