[Fiware-tech-help] Cep

Tali Yatzkar-Haham TALI at il.ibm.com
Sun Aug 23 08:49:52 CEST 2015


Hi Denis,

Glad to hear that you are using the CEP as part of your application!

One possible solution to the problem you described is to review the EPAs 
and the temporal context definitions and make sure the definitions are 
defined taking into consideration performance and memory consumption. 
Make sure that temporal contexts are terminated when no longer needed 
(using event or relative time terminators). Otherwise the number of open 
contexts can grow over time and cause the problem you mentioned. 
In an EPA of type Sequence, the detection time grows significantly if more 
and more input events are processed, a solution for that is to set the 
participant event "Consumption" policy to "Consume". 
Another good thing is to mark an EPA cardinality policy to "Single" if you 
want it to be detected only once.

Another option is that there is internal CEP implementation problem. We 
saw such behaviour in another CEP application and we currently analysing 
it to see if there is an internal problem. In the other application, as a 
temporal work around we restarted tomcat every month to clean the memory. 

Since we are having many users and many support requests, we started to 
document our answers in StackOverflow to help us and our users community. 
It would be very helpful for us and the community if you could post this 
question there. If you agree, please send me the link to your question, 
and I will post this answer there as well. Thank you very much in 
advanced! 

(I cc fiware help list, in order to have this correspondence documented in 
FIWARE issue system)

Best regards,
Tali

Tali Yatzkar Haham
Smart Decision Solutions
IBM Research - Haifa, Israel
tali at il.ibm.com 972-4-8296320
 



From:   Denis Ermacora <ermacora at datamind.biz>
To:     Tali Yatzkar-Haham/Haifa/IBM at IBMIL
Date:   21/08/2015 02:36 PM
Subject:        Cep



Hi, Tali.
I wrote you some months ago about the Complex Event Processing sintax 
and you gave me very useful information.
Now the application we developed that uses CEP as a Tomcat web service 
is fully functional and works well.
The only problem I noticed is that the reaction time of the internal 
engine in response to new events worsens rapidily. The more the engine 
is fed with new events the higher the response time. I suppose it is due 
to the fact that some of the internal events processed in previous calls 
to the service remain in the engine internal tables. I wonder if there 
is a way , for example, to make the CEP destroy explicitly all the 
events within a given segmentation context. Thanks in advance for the 
answer.

best regards,

Denis.

-- 
Denis Ermacora

Research and Development
DataMind S.r.l.
Parco Scientifico e Tecnologico
Via J. Linussio 51,
33100 Udine - Italy

Tel: 0432-629778
Fax: 0432-603887
ermacora at datamind.biz

C.F. & P.I. 02438900306


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.fiware.org/private/fiware-tech-help/attachments/20150823/b5cbc0d0/attachment.html>


More information about the Fiware-tech-help mailing list

You can get more information about our cookies and privacy policies clicking on the following links: Privacy policy   Cookies policy