twalthr commented on a change in pull request #6504: [FLINK-10068][docs] Add documentation for RocksDB-based timers and st… URL: https://github.com/apache/flink/pull/6504#discussion_r208950079
########## File path: docs/dev/stream/operators/process_function.md ########## @@ -277,19 +277,18 @@ Both types of timers (processing-time and event-time) are internally maintained The `TimerService` deduplicates timers per key and timestamp, i.e., there is at most one timer per key and timestamp. If multiple timers are registered for the same timestamp, the `onTimer()` method will be called just once. -**Note:** Flink synchronizes invocations of `onTimer()` and `processElement()`. Hence, users do not have to worry about concurrent modification of state. +<span class="label label-info">Note</span> Flink synchronizes invocations of `onTimer()` and `processElement()`. Hence, users do not have to worry about concurrent modification of state. ### Fault Tolerance Timers are fault tolerant and checkpointed along with the state of the application. In case of a failure recovery or when starting an application from a savepoint, the timers are restored. -**Note:** Checkpointed processing-time timers that were supposed to fire before their restoration, will fire immediately. +<span class="label label-info">Note</span> Checkpointed processing-time timers that were supposed to fire before their restoration, will fire immediately. This might happen when an application recovers from a failure or when it is started from a savepoint. -**Note:** Timers are always synchronously checkpointed, regardless of the configuration of the state backends. -Therefore, a large number of timers can significantly increase checkpointing time. -See the "Timer Coalescing" section for advice on how to reduce the number of timers. +<span class="label label-info">Note</span> Timers are always asynchronously checkpointed, except for the combination of RocksDB backend / with incremental snapshots / with heap-based timers (will be resolved with `FLINK-10026`). Review comment: It would be great if you could add more internal knowledge if there is more to say. This section is very tiny but I guess a lot of work went it to so we should document it accordingly. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
