[jira] [Created] (FLINK-4942) Improve processing performance of HeapInternalTimerService with key groups

[Shang Yuanchun (Jira)]

Stefan Richter created FLINK-4942:
-------------------------------------

             Summary: Improve processing performance of HeapInternalTimerService with key groups
                 Key: FLINK-4942
                 URL: https://issues.apache.org/jira/browse/FLINK-4942
             Project: Flink
          Issue Type: Improvement
            Reporter: Stefan Richter


Currently, key groups awareness in `HeapInternalTimerService` is basically implemented as (hash) map of (hash) sets. Purpose of this is grouping key groups together in a way that allows easy serialization into key groups.

However, this data layout comes along with some significant performance decrease, in particular when the number of key groups is high.

I suggest to keep all timers in one set again at runtime, thus being as fast as in previous versions without key groups.

Instead, we can perform a very fast online partitioning into key groups before a snapshot.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)