August 25, 2011

Renaming CEP … or not

One of the less popular category names I deal with is “Complex Event Processing (CEP)”. The word “complex” looks weird, and many are unsure about the “event processing” part as well. CEP does have one virtue as a name, however — it’s concise.

The other main alternative is to base the name on “stream processing” instead.* The CEP-or-whatever industry is split between these choices, with StreamBase currently favoring “CEP” (despite its company name), IBM emphatically favoring “stream”, and Sybase seemingly trying to have things both ways.

*And then, of course, there is “event stream processing”, regarding which please see below.

I’ve been juggling this terminological divide myself, referring to complex event/stream processing as long as four years ago. But enough is enough. I’d like to write more about the category without repeatedly apologizing for its name. And so, always bearing in mind Monash’s Third Law of Commercial Semantics, here’s where I’m coming down.

The more I think about it, the less I like the term “event processing”. Here’s why. Events happen; data is produced; CEP systems most commonly try to identify and categorize the events based on the data. The CEP systems may then do significant further processing, but more often they just pass the information on to another system (most commonly either persistent DBMS or “real-time” business intelligence). How much of that is really “event processing”? Relatively little, I’d say. And referring specifically to “complex” events doesn’t address my complaints at all.

So I’d like to go with some version of “stream”. But “stream processing” has other computer-related uses, while “Stream management” commonly describes care and planning for small waterways. So “stream” might do best with a modifier, such as “event” or “data”. Of the two, I prefer “data stream” (or “datastream”) to “event stream”; the events aren’t really streaming, but the data is.

So should it be “data stream processing” or “data stream management”? Well, the only one of numerous Wikipedia definitions I’ve actually liked while researching this post is the one for “Data Stream Management System“:

A Data Stream Management System (DSMS) is a set of computer programs that controls the maintenance and querying of data in data streams. The use of a DSMS to manage a data stream is roughly analogous to the use of a Database Management System (DBMS) to manage a conventional database.

A key feature of a DSMS is the ability to execute a continuous query against a data stream. A conventional database query executes once and returns a set of results for a given point in time. In contrast, a continuous query continues to execute over time, as new data enters the stream. The results of the continuous query are updated as new data appears.

I think the data stream/database management analogy is spot on. Your queries work a little differently, but otherwise you’re doing pretty much the same things. Indeed, you’re probably even going to persistently store some of the data, and ideally that DBMS capability would be tightly integrated into your CEP system. (In practice they’re apt to be more loosely coupled; for most purposes that works well enough.) Query execution, data ingestion, performance monitoring/tuning, workload prioritization — it’s very DBMS-like stuff. And by the way, “data stream management system” is the term that was used by the researchers — Mike Stonebreaker, Stan Zdonik, Dan Abadi, et al. — who wrote a paper describing the project on which StreamBase was based … although some might question whether that particular observation is a strong signal of accuracy. 😉

This reasoning suggests Data Stream Management System is what it should be. The usual kinds of abbreviation — datastream (product), datastream manager, DSMS, etc. would no doubt follow. So should it be “Data Stream”, “Datastream”, or “Data-stream”? At that level of detail, I don’t yet have an opinion.

The only thing is — that’s all pretty wordy compared to CEP. So after all this, I’m still not sure which term(s) I prefer.

What are your thoughts?


29 Responses to “Renaming CEP … or not”

  1. Scott Fingerhut on August 26th, 2011 12:57 am

    Sorry, the word “stream” just serves to severely narrow the applicability of CEP. And, yes, I come from a vendor perspective (having served to launch Tibco’s CEP product and now with Informatica’s CEP). Gartner would also disagree with you and so would the father of CEP (David Luckham) who has a book coming out on the subject. “stream processing” is one form of CEP.
    We’ve deployed CEP solutions that are customer driven meaning some have streams, some are batch intervals and some combine both. The key is that they are looking for less-than-simple (albeit not always complex) relationships in a timely manner so they can act before issues grow.

    Finally, don’t ever try to turn the acronym into a word like “Sep.” That’s just bad mojo.

  2. Curt Monash on August 26th, 2011 2:37 am


    Here’s where I’m coming from.

    Either the data can be (economically/realistically/whatever) persisted before it’s filtered, or it can’t. If it can, it probably should be, so it’s not clear to me why one would use CEP. If it can’t, it’s a lot like a stream.

    What do you think I’m missing here?

  3. Tony Baer on August 26th, 2011 8:57 am


    I share with you your distate for the name “Complex Event Processing.” Not only does the name violate Monash’s Law, but it also violates the first law of marketing, which ios not to name something “complex” unless you want nobody to buy it.

    And as you say, stream processing & event stream processing have their own sets of baggage or specific interpretations. The issue I see with characterizing this as Data Streams is that (maybe in my mind only) it implies something singular and transactive: something happens and a piece of data is generated. OLTP is a form of event processing — as an event generates a set of data that in enterprise operaitonal systems are often processed as transactions. But that’s not what we’re talking about here, and of course that is only the simplest form of event processing. (Of coruse I’m not implying that transaciton processing, with need for ACID support, is simple!).

    Event processing of the complex — or maybe compound — side typically deals not with single happenings that generate individsual bits of data, but combinations of “things” that happen that generate multiple bits of data. Most of what is called CEP strives to isolate patterns of things (avoiding the term “events” here) that happen, and make that information actionable.

    So while I like terms that include “stream” in it, to avoid baggage with that or other terms, let’s use the term “compound” as this sets this form of event processing apart from OLTP.

  4. Ron Ross on August 26th, 2011 9:06 am


    Although possibly on-target for current products and their technical orientation, I disagree with you here in the bigger picture. Events are simply a different primitive than what data represents (things). So I believe the suggested name takes the focus off-target. Perhaps “Event Stream Management” would be better.

    Why does this interest me? Sooner or later, techniques and tools for business analysis need to come to grips with business events. This focus is essential for truly supporting business rules and know-how management. “Events” belong right up there with the other five primitives: things, processes, locations, roles, and goals. (Yes, there’s six — it’s a Zachman view.)

  5. Daniel Weinreb on August 26th, 2011 9:12 am

    If you’re getting votes, another possible voter would be Prof. Michael Franklin at U.C. Berkeley, who has done research on this and, I think, a startup making such a product. He presented this at the New England Database Summit a few years ago (the product).

  6. Darach Ennis on August 26th, 2011 9:48 am

    Hi Curt,

    I agree with both Giles Nelson (Progress / Apama, discovered this post via him on Twitter) and Tony Baer above. The term CEP is problematic at best.

    The term ‘Lean Data Management System’ comes to mind.


  7. Opher Etzion on August 26th, 2011 1:02 pm

    I also prefer not to use the term “complex event processing”, I also think that three letter acronyms are typically marketing buzzwords, while disciplines consist of two words: image processing, information retrieval, data mining and more..

    The two words I prefer to use is “event processing” and not “stream processing”, since “event” has a semantic meaning of something that happens, the happening is of certain type, it occurred in certain time, in certain place, transitioned certain states etc, which are fundamental to the type of processing, while “stream” is a collection of data in motion, which may be of various types: voice streams, video streams and more, whose processing is somewhat different. It is also interesting to note that products that are descendants of academic projects classified under DSMS label themselves as (complex) event processing.



  8. Curt Monash on August 26th, 2011 2:41 pm


    You’re talking about Michael Franklin’s oft-repositioned company Truviso.

  9. Curt Monash on August 26th, 2011 2:42 pm


    But some of the core uses of the technology might be to try to recognize something in, say, an audio stream.

  10. Curt Monash on August 26th, 2011 2:43 pm


    How close is the match between what CEP does and the “events” you are talking about?

  11. Curt Monash on August 26th, 2011 2:43 pm


    So if there’s only a single stream of data it’s not permissible to use this technology? 😉

  12. Opher Etzion on August 27th, 2011 4:30 am

    Hi Curt.

    Stream platforms which are “programming-in-the-large” platforms indeed can have any type of nodes like processing audio streams.

    Event processing languages are dealing with – filtering, transformation, and pattern matching within contexts, based on the event semantics; processing audio streams is a different technology

    One can implement event processing languages on top of stream processing platforms, but this is not the only implementation, I’ve posted longer response on my Blog:



  13. Scott Fingerhut on August 29th, 2011 10:15 am

    Google, Yahoo, Microsoft – those are all names that surely were debated with some degree of fist pounding over the lunacy of how they all sound. What happened? They made the name a reality not the other way around.

    CEP is just a 3-letter acronym trying to describe a concept – much like a ton of other spaces. Which, by the way, businesses generally don’t care about. We in tech seem to need to throw these TLAs as though there are a host of suitors in waiting.

    You could hold BI as a shining example of a successful TLA (two-letter in this case), but the business really knows this as reporting and analysis.

    CEP will be more defined by the end-uses than by itself. And, it certainly is NOT only streams of data. There’s a much bigger debate among vendors, methods. I do have to point out that “rules” are a critical component, and surprised that the term has been mentioned just once in this discussion.

  14. Colin on August 29th, 2011 12:09 pm


    You’re mistaking the how with the what when you refer to persistence. Whether or not you persist an event is immaterial.

    What is material is what differentiated event stream processing, at least initially, from event processing (where we never persisted the events either – anyone remember NEON, or MQ Series Integrator?). Those areas of differentiated were:

    1) dsl
    2) continuous query
    3) length or time windows
    4) temporal pattern matching

    Most of these features can now be found in larger, more well established platforms from firms like Tibco, Progress, and Informatica. Those platforms offer far more than what any CEP engine focused vendor, like Streambase or Sybase, come close to offering.

    CEP isn’t a market. It’s a couple of features.

    The firms who have come closest to implementing what David’s original book have focused more on the business issues – CEP was supposed to get us closer to understanding what was going on in our domain, finding causality, refining our approach, and the implemented incremental changes quickly. It was supposed to give us insight and actionable intelligence (a phrase hijacked by Sybase lately)

    As you can see, most people in the world of CEP probably haven’t even read that book. If they had, we’d be focused on things other than speeds and feeds.

    And wouldn’t care so much about which TLA to use either.

    Just my 3 cents.

  15. Cloud Database on August 31st, 2011 3:35 pm

    I prefer derivatives of “stream” as well, but why does Streambase favor CEP, I would think they would love to brand the space with a derivative of their name…just basic marketing I would think.

    – Mike

  16. Curt Monash on August 31st, 2011 5:33 pm

    Streambase’s choice is probably connected to industry focus — in the algorithmic trading market, “CEP” does actually make sense and have well-deserved traction.

  17. Roger Rea on August 31st, 2011 7:46 pm

    Curt … what a delightful discussion you sparked! As you know, I prefer Stream Processing. But, “What’s in a name? That which we call a rose
    By any other name would smell as sweet.” To take this further, can CEP detect odors? colors of a flower at a certain time of day? The marketplace will decide what to call these things. What’s more important to customers than a name, is whether or not they can economically solve a business problem.

    Roger Rea
    IBM InfoSphere Streams Product Manager

  18. Cloud Database on September 2nd, 2011 3:24 pm

    Curt, I understand Streambase’s rationale from a technical perspective, don’t get me wrong. But defining a sector after your name…huge! It is like being a Kleenex, Xerox, Google…all corporate names that have come to generically define a things or action. BTW, great seeing you on your last trip, always challenging, insightful and fun.

    – Mike

  19. Shivnath Babu on September 3rd, 2011 9:09 am


    I like to fondly think that Shivnath Babu and Jennifer Widom came up with the term “Data Stream Management System (DSMS)” in a vision paper we wrote in late 2000 (part of the Stanford STREAM project and published in the 2001 SIGMOD Record: Maybe this is the place to find out that my assumption was wrong.

    It is nice to see the interest in data stream processing (or CEP) coming back, in particular in the database research conferences like SIGMOD and VLDB. Data stream management was the hot research topic in the 2000-2004 time frame, and then the focus shifted to stored big data (MapReduce, column stores, etc.). Integrating high-speed stream processing and big data processing in easy ways seems very challenging. A post on that would be timely.

    — Shivnath Babu

  20. Curt Monash on September 3rd, 2011 9:39 pm


    I’m not aware of anything that undercuts your priority claim.

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