These days I am working on a task to improve the performance of a wso2telco analytics which is based wso2 DAS. Our product does data summarizing using apache spark. When the data increases it hangs even though we have applied wso2 incremental processing. Hence we decided to do one level data summarizing on real time as soon as data arrives at wso2 siddhi event processor. spark will do summarize per hour while siddhi will summarize per minute. To summarize data in real time we can use siddhi window feature. it can hold the events arrived up to a specified time and then release all the accumulated events at once. Since the events received are released at once we can use summarizing methods to summarize them. Following describes few attempts how I tried to do this. Attempt 01 This was the attempt suggested by wso2 support team https://github.com/wso2/analytics-apim/blob/master/features/org.wso2.analytics.apim.feature/src/main/resources/template-manager/executionplans/AP...