Re: [rules-users] Drools and event based decisions, i.e. streaming market quotes

Henry Canterburry wrote: > Mark, > > Thanks for the reply. My timeframe matches the one you mentioned > although I would naturally be looking for working and production > ready functionality. In the meantime, did any of the approaches I > mentioned make any sense or would you say that drools is not the > right tool at this point? I do have helper classes and other > intermediary data caching approaches at this time that permit me to > query past data and an entire streaming architecture to feed data. > > Thanks > HC > > > Mark Proctor wrote: >> What's your time scale for this? We are currently implementing CEP >> extendions to the language and engine which will do all of this for >> you, we'll have a milestone release out in february when you can >> first play with this and aiming to get a full release end of Q1 >> start of Q2. >> >> Mark >> Henry Canterburry wrote: >>> What would be the best approach using drools to handle event driven >>> decisions based on streaming data? In my case I am looking for a >>> typical stock market scenario. Ticker quotes usually come in at >>> second increments and depending on how many ticker symbols you >>> subscribe to at any one time, there can be a lot of data coming and >>> and changing every second. However, there probably isn't a need to >>> keep large quantities of historic data in memory...maybe the last >>> 200-500 ticks. The outputs are if a stock should be sold or bought, >>> at what quantity and what price. Once the decision has been made, >>> we need to make sure it does not persist past the point of being >>> valid given the state of that data. >>> >>> If I have rules that are meant to derive/calculate info and >>> decisions from the streaming data, what is the best integration >>> architecture for the rule engine with the rest of the application? >>> >>> Stateful session which constantly updates the ticks in working >>> memory and queries the memory for results on an ongoing basis? In >>> this case, the session would be kept alive for as long as the data >>> stream is going (i.e. hours)? This approach would require very >>> rigorous working memory management and all the objects in it. >>> >>> Or...loop constantly over a stateless session for each tick? This >>> would reduce the need to manage the number of objects in working >>> memory since only the amount needed would be inserted in the first >>> place and read back the results? Sounds inefficient and with lots >>> of overhead. really don't know. Try the stateful approach first and see how that pans out. >>> >>> Also, what about multi-threaded environments? Any potential for >>> conflicts between concurrent session instances? events are normally stateless, so you should have no problem there. Mutable objects in different threads being updated is of course a problem, shadow proxies can help a little there - but you still need to be careful. >>> >>> Thanks >>> HC >>> >>> >>> _______________________________________________ >>> rules-users mailing list >>> rules-users(a)lists.jboss.org >>> https://lists.jboss.org/mailman/listinfo/rules-users >>> >> >> > >