title: Esper - pattern detection
body: <p>I have a question for the community regarding pattern detection with Esper.</p>
  
  <p>Suppose you want to detect the following pattern among a collection of data : A B C</p>
  
  <p>However, it is possible, that in the actual data, you might have: A,B,D,E,C. My goal is to design a rule that could still detect A B C by keeping A B in memory, and fire the alert as soon as it sees C.</p>
  
  <p>Is it possible to do this? With the standard select * from pattern(a = event -> b= event -> c=event), It only outputs when the three are in sequence in the data, but not when there are other useless data between them</p>