Why do companies purchase a product known as Complex Event Processor (TIBCO Streambase CEP, IBM Infosphere CEP) or download Open Source (Siddhi, Esper)?
I understand why companies use real-time analytics in general to make sense of real-time data streams, but I don't understand why CEP.
"Complex event processing (CEP) uses patterns to detect composite events in streams of tuples."
CEP also joins many streams and finds patterns among the whole.
But I don't get it why use CEP and not Spark? Is there any use case you can explain this on?