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đ
flink_window_assigners
Time based â
| Type | Description |
|---|---|
| Tumbling | Fixed-size, non-overlapping windows > Each event belongs to exactly one window. |
| Sliding | Fixed-size windows that overlap > An event can belong to multiple windows. |
| Session | Dynamically sized windows based on inactivity gaps between events |
- Have both event / processing time flavours
- Tradeoffs
- Processing:
- đ Lower latency
- âšī¸ Cannot correctly process historic data
- âšī¸ Cannot handle out of order data
- âšī¸ Non deterministic data
- Processing:
Count basedâ
| Type | Description |
|---|---|
| Tumbling | Processes a fixed number of events before triggering (non-overlapping) |
| Sliding | Processes a fixed number of events with overlap |
- Windows will not fire until a batch is complete
- No option to timeout / process a partial window (except with a custom trigger)
Globalâ
- Assigns every event with the same key to the same global window
- Useful for custom windowing, with a custom Trigger
NOTE
Apache flink suggests to use ProcessFunction instead