Overview to Source Windows

At least one Source window is required for each continuous query. All event streams enter continuous queries by being published or injected into a Source window. Event streams cannot be published or injected into any other window type.

Source windows are typically connected to one or more derived windows. Derived windows can detect patterns in the data, transform the data, aggregate the data, analyze the data, or perform computations based on the data.

Source windows accept streaming data or raw data files through in-process connectors or executable adapters. Source windows can also accept data from the publish/subscribe API, HTTP clients, or by injection from the C++ Modeling API.

Ordinarily, a Source window queues incoming events until downstream derived windows are free to process them. Because event blocks are never dropped, there might be considerable backup in the Source window whenever downstream processing is significant or resources are limited. You can use the queue-height parameter to set the size of the input queue. At times it can be useful to not queue incoming events at all, processing only the latest event. Use the shed-input parameter to force the Source window to process only the latest available event block and avoid backup.

For information about the XML elements associated with Source windows, see window-source in SAS Event Stream Processing: XML Language Reference for Event Stream Processing Models