What difference between Flink time window and slide time window?

I'm investigation how Apache Flink works and trying to understand time windows in Flink.

1 answer

  • answered 2017-10-20 13:13 Jicaar

    The documentation outlines this well: https://ci.apache.org/projects/flink/flink-docs-release-1.3/dev/windows.html

    A simple TimeWindow is actually a Tumbling(Event/Processing)TimeWindow and a Sliding(Event/Processing)TimeWindow is a sliding window.

    To give specific examples from the documentation (see link for illustrations):

    Tumbling Window

    A tumbling windows assigner assigns each element to a window of a specified window size. Tumbling windows have a fixed size and do not overlap. For example, if you specify a tumbling window with a size of 5 minutes, the current window will be evaluated and a new window will be started every five minutes.

    Sliding Window

    The sliding windows assigner assigns elements to windows of fixed length. Similar to a tumbling windows assigner, the size of the windows is configured by the window size parameter. An additional window slide parameter controls how frequently a sliding window is started. Hence, sliding windows can be overlapping if the slide is smaller than the window size. In this case elements are assigned to multiple windows.

    For example, you could have windows of size 10 minutes that slides by 5 minutes. With this you get every 5 minutes a window that contains the events that arrived during the last 10 minutes.