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https://issues.apache.org/jira/browse/FLINK-9513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16523640#comment-16523640
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ASF GitHub Bot commented on FLINK-9513:
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Github user StefanRRichter commented on the issue:
https://github.com/apache/flink/pull/6196
Thanks for the nice contribution. I had some comments inline. In particular
three points about the serializer. I would suggest to avoid the use of raw
types. I would also suggest to avoid using streaming API at least methods that
can appear in hot loops (mainly copy, de/serialize) for performance reasons. I
think the imperative style code will not even be (much) longer in those cases.
Last, I suggest to always test new serializers via the `SerializerTestBase`
because this catches many problems with little effort.
> Wrap state binder with TTL logic
> --------------------------------
>
> Key: FLINK-9513
> URL: https://issues.apache.org/jira/browse/FLINK-9513
> Project: Flink
> Issue Type: Sub-task
> Components: State Backends, Checkpointing
> Affects Versions: 1.6.0
> Reporter: Andrey Zagrebin
> Assignee: Andrey Zagrebin
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.6.0
>
>
> The main idea is to wrap user state value with a class holding the value and
> the expiration timestamp (maybe meta data in future) and use the new object
> as a value in the existing implementations:
> {code:java}
> class TtlValue<V> {
> V value;
> long expirationTimestamp;
> }
> {code}
> The original state binder factory is wrapped with TtlStateBinder if TTL is
> enabled:
> {code:java}
> state = ttlConfig.updateType == DISABLED ?
> bind(binder) : bind(new TtlStateBinder(binder, timerService));
> {code}
> TtlStateBinder decorates the states produced by the original binder with TTL
> logic wrappers and adds TtlValue serialisation logic:
> {code:java}
> TtlStateBinder {
> StateBinder binder;
> ProcessingTimeProvier timeProvider; // System.currentTimeMillis()
> <V> TtlValueState<V> createValueState(valueDesc) {
> serializer = new TtlValueSerializer(valueDesc.getSerializer);
> ttlValueDesc = new ValueDesc(serializer, ...);
> // or implement custom TypeInfo
> originalStateWithTtl = binder.createValueState(valueDesc);
> return new TtlValueState(originalStateWithTtl, timeProvider);
> }
> // List, Map, ...
> }
> {code}
> TTL serializer should add expiration timestamp
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