Re: [rules-users] Insert to non-existing entry point causing NPE in drools server?
On 11/12/2013, dunnlow <dunnlow(a)yahoo.com> wrote:
Hmm, whelp, no, nothing empirical. I think in my head I am combining
a few
things I've read.
In the Developers Cookbook (pg130) there is a comment that entry points can
help reduce cross products and can be used to partition memory. I remember
reading that the entry points are built during compile time, so I read that
to mean that if I have 1000 rules, but only 1 rule with entry point "ep1"
that if I insert a fact to ep1, the engine has already built the structure
to only evaluate that 1 rule. I thought that was the main reasoning behind
entry points :-/ You are saying that my thinking here is incorrect?
Entry points (or streams) have been added for representing different event
data sources. I would not think highly of such a feature if its foremost intent
would be memory optimization, i.e., passing the implementor's buck to the
user. Now entry points may have the effect you have concluded from these
statements - your reasoning may very well be correct. But there's no doubt
that entry points are a static, compile time issue, and you are reporting
a problem due to dynamic variations in the data. Using an iffy optimisation
and trying to come to grips with it illustrates Michael A Jackson's
pair of rules for optimisation ;-)
To summarize: I wouldn't go up this alley unless I had data that would
show it's worth the effort.
So, in the manual
(http://docs.jboss.org/drools/release/6.0.0.Final/drools-docs/html/DroolsC...)
during the banking example for entry points, there is little difference
between having an "ATM Stream" and "Branch Stream" as shown and
adding a
"stream" attribute to the WithdrawRequest object and adding the constraint,
stream=="Branch"?
Given the problems arising from changing the SW at the *source* of
these streams to accomodate the additional property: there is a big
difference. As for the efficiency of the rules, I'd hold my judgment
until after the benchmark :-)
Cheers
Wolfgang
Thanks again
laune wrote
> What makes you think that using entry points "speeds things up"? The
> Engine still has to evaluate the entry-point attribute of a fact
> (handle),
> just like any other attribute.
>
> Or do you have conclusive evidence based on solid benchmarks?
>
> -W
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