Trick: Sending Streams Application Standard Output to Terminal

When working on a Streams application, you often add Custom operators and trace statements in your applications to debug and understand what is happening.  This is done by adding println statements in the logic clause of the Custom operator. To get the most up-to-date application output, you normally repeatedly gather the console logs for the PE in Streams Studio...  Continue reading Trick: Sending Streams Application Standard Output to Terminal

Incremental Checkpointing in Streams V4.1

The Streams V 4.1 release features the Incremental Checkpointing of operator state as one of the enhancements to the application High Availability and Guaranteed Tuple Processing. What Is Incremental Checkpointing? Since Streams V4, an operator can implement the StateHandler interface and implement the StateHandler::checkpoint() and StateHandler::reset() callback functions to checkpoint and restore its state, respectively. The checkpoint()...  Continue reading Incremental Checkpointing in Streams V4.1

Catching exceptions in SPL

Up to Streams 4.0.1, a processing element (PE) gracefully shuts down when any of its operator throws an exception. Many times, this behavior is desired, as the SPL runtime cannot guarantee that the operator will have a correct state after throwing an exception. Other times, it can cause unnecessary shutdowns and tuple loss when processing...  Continue reading Catching exceptions in SPL