World's fastest rules engine

PST's new, parallelized rules execution engine is massively more scalable than IBM's, Oracle's, Fair Isaac's, Red Hat's, and the rest

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Rules execution benchmark results

  WaltzDB-16 WaltzDB-200
JBoss Drools (Rete) 0.994 Not tested
IBM/ILOG JRules (Rete) 0.640 Not tested
Fair Isaac Blaze Advisor (Rete-2) 0.305 Not tested
OPSJ Rete-2 0.262 17.466
OPSJ Rete-NT 0.433 2.362

JRules, Drools, and a number of other execution engines all use what they call an enhanced version of Rete that does improve performance. Except for PST's OPSJ, only Blaze Advisor uses Rete-2, which Fair Isaac licenses from PST. The original Rete algorithm, which Forgy developed with DOD money, belongs to the public domain.

You might notice that WaltzDB-16 takes longer to run on Rete-NT than on Rete-2. This is because it takes only a few microseconds to build the straight-up Rete or Rete-2 "network," but just a wee bit longer to build the more complex Rete-NT network that will handle anything you can throw at it. This overhead is a small price to pay. Considering that the number of rules and objects in a system always grows, you might as well start with the best maximum performance for the first implementation. You can count on any rulebase system to grow by a factor of four in a couple of years.

The Rete-NT algorithm is at least 500 times faster than the original Rete and 10 times faster than Rete-2. It will allow massive amounts of data and huge numbers of rules to be used to solve complex problems almost instantly -- before a scam artist completes a fraudulent credit card transaction or a terrorist boards an airplane, for example. For companies trying to track, say, millions of credit card users or thousands of airline passengers, and apply thousands of rules to reach an answer within a second or two, Rete-NT opens up new possibilities.

The main purpose of a BRMS is to allow the business rules in complex applications to be quickly and easily changed in response to business needs. Several vendors (IBM, Oracle, Fair Isaac, Pegasystems, Visual Rules, and so on) have succeeded in making this process as simple as possible, even allowing business users to enter and modify the rules directly. Now the problem is performance. The cross-matching of millions of objects and thousands of rules can run into the trillions of comparisons for just a single execution. With PST's Rete-NT, we finally have a rulebase engine up to the task.

James Owen is senior consultant and architect at Knowledge-Based Systems Corporation and contributing editor to InfoWorld. 

This article, "World's fastest rules engine," was originally published at Follow the latest developments in applications, application development, and enterprise data management at

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