GitHub user bowenli86 opened a pull request:
https://github.com/apache/flink/pull/5236
[FLINK-8322] support getting number of existing timers in TimerService
## What is the purpose of the change
There are pretty common use cases where users want to use timers as
scheduled threads - e.g. add a timer to wake up x hours later and do something
(reap old data usually) only if there's no existing timers, basically we only
want at most 1 timer exists for the key all the time
## Brief change log
Discussed with Aljoscha that we should use extra data structures to keep
track number of timers. I decided to use Guava's Table to store `<Key,
Namespace, NumberOfTimers>`.
## Verifying this change
This change added tests and can be verified as follows:
`HeapInternalTimerServiceTest`, `KeyedProcessOperatorTest`, and
`KeyedCoProcessOperatorTest`.
## Does this pull request potentially affect one of the following parts:
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: (yes)
## Documentation
- Does this pull request introduce a new feature? (yes)
- If yes, how is the feature documented? (JavaDocs)
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/bowenli86/flink FLINK-8322
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/5236.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #5236
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commit 8578eb6678ad54169e1769b8e69391a388d1d40a
Author: Bowen Li <bowenli86@...>
Date: 2018-01-02T19:21:28Z
update local branch
commit b81a8e2aebe4d9cd61baef3904d1e6bef0d1702a
Author: Bowen Li <bowenli86@...>
Date: 2018-01-03T07:51:09Z
[FLINK-8322] support getting number of existing timers in TimerService
commit 483c8a20ef6c2390d1491724755fbd95e88eb278
Author: Bowen Li <bowenli86@...>
Date: 2018-01-03T08:03:48Z
add comments
commit 4c225df508ebb03acc0cd68c77681977161403f6
Author: Bowen Li <bowenli86@...>
Date: 2018-01-03T08:38:24Z
update unit tests
commit 8876add25b7fbf576c045148cc35cee4086cb901
Author: Bowen Li <bowenli86@...>
Date: 2018-01-03T09:12:57Z
add unit tests
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