Adding a Persistent Subscribe Pattern

Persistent Subscribe Pattern (PSP) is used to implement Guaranteed Delivery (GD) in output adapters. PSP involves a combination of an input window, a control window (also known as a truncate window), and a Flex operator with a log store.

1. Choose the window you would like to support GD.
2. (Optional) If a window that you want to support GD doesn't already exist, create a new window:
   1. In the Visual editor Palette, in Streams and Windows, click Input Window.
   2. Select a location in the diagram and click to add the shape.
3. Right click the window and select Modify>Add Persistent Subscribe Pattern.
4. In the Select Store dialog, select either Create New Store or an existing store, and then click OK.

   A Flex operator, named <input window name>_log<number> and a truncate window named <input window name>_truncate<number> are created. The truncate window and the input window connect automatically to the Flex operator.

   Note: Though you have created a PSP, it can only implement GD if you attach an appropriate output adapter to the Flex operator.