[rules-users] Loading facts and memory size limits

[Swindells, Thomas]

The easiest way to view drools is as an in memory relational database.
Rules are a type of efficient triggers that as soon as data changes causes actions to occur in nearly real time. (Sorry for making people cringe with this overly simplified explanation).

The use case you gave sounds like you are trying to perform a scheduled task which every so often queries a database to select a category of people to perform some actions on.  This is most likely to be most efficiently done by just doing a sql query to get the relevant data and processing it in the traditional way, though you may want to use Flow to manage the perfoming and defining of the actions.  Of course if your use case is actually more complicated than this then you may want either a hybrid approach (a simplified sql query to produce a superset of who will be effected and then more complex rules to pick out individual customers with more specific criteria), or CEP approach may work - although you will need to be careful that your CEP rules don't have the effect of keeping all 6 months worth of data in memory.

Thomas
> -----Original Message-----
> From: rules-users-bounces at lists.jboss.org [mailto:rules-users-
> bounces at lists.jboss.org] On Behalf Of bellios
> Sent: 09 September 2010 09:28
> To: rules-users at lists.jboss.org
> Subject: Re: [rules-users] Loading facts and memory size limits
>
>
> In my application I would to model the Customers-Sales domain and I thought
> that drools could help me to express a set of rules to capture (or execute
> on-demand) some "special" customers (e.g. take the customers which not
> have/have bought some products of category X in the last 6 months).
>
> To do this i'm loading the last 6 months sales into WM, afterwards on demand
> i execute the rules. This process fails due the memory requirements. I
> thought that Drools would use an hibernate/JPA/  or an incremental
> mechanisms to load and process the facts.
>
> @Swindells, Thomas: Do you think that it's the right approach?
>
> @Michael Anstis-2: I will try to study in deep the event
> processing\CEP\streaming methods.
> --
> View this message in context: http://drools-java-rules-
> engine.46999.n3.nabble.com/Loading-facts-and-memory-size-limits-
> tp1440236p1444747.html
> Sent from the Drools - User mailing list archive at Nabble.com.
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