Latency Takes a Back Seat to Accuracy in CEP Applications

Opher asks, The only motivation to use EP COTS is to cope with high performance requirements” – true or false?.

The answer: True and False.

If high performance is discussed in the context of event processing speed and latency, then it is Absolutely False that speed and latency are the most important performance criteria for event processing applications. 

Detection accuracy (the performance of the detection algorithms for detecting derived events or situations) is the most important criteria, hands down. 

Emerging CEP/EP applications are centered around the concept of detecting (and acting upon) opportunities and threats in real-time.   The most important performance criteria is the confidence in the detection of the derived event, or situation, depending on your EP vocabulary.

For example, one of the most promising areas for CEP/EP applications is fraud detection.   There is a fundamental tradeoff in most, if not all, detection-oriented systems – the tradeoff between false positives and negatives.  The same is also true for cybertrading and other detection-oriented applications. 

If you miss an opportunity or threat, it does not matter how fast you missed it, or how low the latency was in processing, you simply missed it!     In theory, you could process events just below the speed of light –  So what?!  Making mistakes faster than others is not considered to be a superior skill that leads to a higher paying job!  (Well, we all have known quite a few who made a lot of mistakes but were buddy-buddy with the boss, but that is another story for another day!)

Likewise, if you detect a false opportunity or threat, if does not matter if you detected it in nanoseconds, or if the latency was just below the the speed of light.   Detecting false positives does not demonstrate superior performance.

Most, but not all, of the current CEP/EP vendors have relatively simple rules-based detection approaches and many have marketed “low latency” as their core capability.  The fact of the matter, well expressed by Kevin Pleiter, highlighted in Complex Event Processing – Believe the Hype? earlier this week, is that performance is critical, if the definition of performance is “accuracy” and “actionable” detection.  Latency takes a back seat to accuracy – as it should.

Kevin echoed what I have been saying for a number of years in the CEP community.  Detection accuracy that leads to high confidence, actionable business decisions is the most important performance criteria for CEP applications.

So, if we define performance in the context of event processing accuracy and confidence in decision making, then the answer is that is it Absolutely True  that performance is one of  the most important criteria for event processing applications. 

Latency discussions are a distraction, a red herring,  something intended to divert attention from the real problem or matter at hand. 

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2 Responses to Latency Takes a Back Seat to Accuracy in CEP Applications

  1. Opher Etzion says:

    Hello Tim.

    This is starting to be an interesting discussion.

    You raise a good point about the accuracy as an important point – and it seems that you agree that latency is not the one, so your claim is that “accuracy” is a major reason for using EP COTS and not hard coding the functionality ? can you say more about the relationship between the two ?

    cheers,

    Opher

  2. […] a medium or relatively low volume of events than with a very high volume of events. Also, Tim is an advocate of EP products with better detection “accuracy” rather than minimum latency or maximum […]

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