Github user StephanEwen commented on the pull request:
https://github.com/apache/flink/pull/854#issuecomment-114396094
The combiner partially sorts the records, to group subsequences in order to
combine (reduce) them.
If a record does not fit into a fresh sort buffer, then we can simply emit
it as it is. There is no assumption on records being emitted in sorted order.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
