If you have an application that uses the Import and Export operators, you might want to change the export properties or import subscription. This article demonstrates how you can do so without having to recompile the application.
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 or Streams Console. This process can be quite cumbersome. Wouldn’t it be nice if you can automatically see the most updated console output in a terminal, without you having to collect the logs? We are going to show how you can do this.
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 a single problematic tuple out of millions.
Streams 4.0.1 introduced the evalPredicate function which allows you to evaluate a predicate specified as rstring (eg “x==5”) for a limited class of predicates. In this post, we’ll use this function to build a filter operator that allows you to update the filter expression at runtime.
This post demonstrates how to write C++ native functions to add functionality to Streams. When we need to wrap a library so that we can use it from SPL, there are two options. One option is to add a new primitive operator. But an alternate choice is to add a native function. A native function is an SPL function where the code is written in C++ or Java.
The Streams Quick Start Guide is intended to help you get up and running with InfoSphere Streams quickly. We will first introduce the basic concepts and building blocks. And then we will write a very simple Streams application, and demonstrate how you can run and monitor this application in the Streams distributed runtime environment.