[BEAM-1517] Garbage collect user state in Flink Runner

• Type: Bug
• Status: Resolved
• Priority: P0
• Resolution: Fixed
• Affects Version/s: 0.6.0
• Fix Version/s: 0.6.0
• Component/s: runner-flink
• Assignee: Jingsong Lee
• Reporter: Aljoscha Krettek
• Created: 21/Feb/17 09:02
• Updated: 24/Jul/20 20:18
• Resolved: 01/Mar/17 17:02

Description

User facing state/timers in Beam are bound to the key/window of the data. Right now, the Flink Runner does not clean up user state when the watermark passes the GC horizon for the state associated with a given window.

Neither StateInternals nor the Flink state API support discarding state for a whole namespace (which is the window in this case) so we might have to manually set a GC timer for each window/key combination, as is done in the ReduceFnRunner. For this we have to know all states a user can possibly use, which we can get from the DoFn signature.

Issue Links

• links to: GitHub Pull Request #2127