Tumbling Window

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Tumbling Window

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A window that specifies a time frame that continually updates over time. For example, a tumbling window might specify a following hour.

In contrast to a sliding or rolling window,  a tumbling window is a collection of rows that are aggregated to produce a fewer number of output rows.  The window is "tumbling" because after the output rows are emitted, the tumbling window is cleared and a new set of future rows are accumulated for the next output. As a result, the total number of output rows are limited. Tumbling windows can be used with streaming aggregation (SELECT STREAM ... GROUP BY).  In contrast, a sliding or rolling window emits an output row with every input row and flush a small number (often times 1) row out of the window for the next calculation. The main difference between the two is that sliding or rolling windows continue to accumulate rows. These are used for windowed aggregation