I am wondering if anyone has any experience in managing very large rule
sets and facts and could share their experiences in the design and
management of this.
We are embarking on a new Student Information System project here at UBC
in conjunction with several other American universities. We have pretty
much decided to use Drools as our rules engine and maybe also the Drools
BRMS for our business rules management. Our first application is the
course curriculum application/module where we will manage course
co-requisites, pre-requisites, etc. and we estimate that we will have
about 20,000 course rules. We currently have about 15,000 course rules
(QuickRules) in production now. We will also have security rules,
input/form validation rules, student awards rules, degree rules,
enrolment rules, admission rules, student financial rules etc. which
will total about 40,000 rules. So currently we are looking at managing
about 60,000 rules (not including versioning). If we include versioning
then there would probably be more than 100,000 rules.
A single course could have 10 or more rules per course version. We
currently have about 2000 course and most courses have more than 1
We are looking into developing our own rules management system to define
dependencies between rules, courses (facts) and course + rule versions.
E.g. Course CHEM101 version 1 links to CHEM101 a single rule or a rule
set/package version 1 by a rule id.
We need the ability to notify users when rules are modified which
impacts other rules and what impact changing a rule can cause for
example a degree program. E.g. changing a course's pre-requisite may
affect other courses' pre-requisites; rules about rules. We also need
the ability to find out why a student was not able to register for a
course etc. We will also need to show the course dependency graph
visually (the RDBMS can probably help us here). Later, we are hoping to
use the Drools Solver for course and exam scheduling and also to use it
for student degree planning and student awards.
We will need to translate the rules into English language syntax for
publication in the course calendar and later into other languages (first
French) since the SIS application will be used internationally. Listing
requirements could just be shown in bulleted form. Probably can't use
the DSL in this case since we would need to support several languages or
maybe I am wrong here?
If we use the Drools BRMS to store all of our rules on a relational
database, will we be able to write SQL queries to get at specific
rules/packages to link facts (courses) to rules? Or do we have to go
through the BRMS to get at the rules. Does BRMS have a facility to
validate rules against facts so you can see if your rules execute
correctly against your data/facts before committing your rules. Or maybe
we need a testing framework for this.
Other issues are the performance of the Drools Solver and having
thousands of rules compiled, loaded and running. During registration we
could have thousands of rules executing concurrently. The rules engine
and the BRMS would be services as part of an SOA infrastructure (and an
OSGi service environment). Anyone got any experience with Drools in an
OSGi environment with respect to class loading issues when compiling
rules and facts from other bundles since rules and facts may be in
different bundles? Bundle buddy class loading?
Later, we will need translators to/from other rule engines; maybe ruleML
and JCR can help us here.
So far, I think Drools can do most of this; am I correct here? Does any
of this sound plausible?
Thanks very much for any tips, thoughts or comments.
Enrolment Services - Student Systems
University of British Columbia