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https://issues.apache.org/jira/browse/KAFKA-4468?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16076281#comment-16076281
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Evgeny Veretennikov commented on KAFKA-4468:
--------------------------------------------
I have researched windowed stores a bit more and noticed, that
{{WindowedDeserializer}} isn't used in Kafka source codes, including internals:
{noformat}
$ grep -Rl WindowedDeserializer | grep java | grep -v test
streams/src/main/java/org/apache/kafka/streams/kstream/internals/WindowedDeserializer.java
{noformat}
It's not a part of API too (as it's in {{internals}} package).
{{RocksDBWindowStore}} doesn't use {{WindowedDeserializer}} to deserialize
windowed keys, but uses {{WindowStoreUtils}} static methods instead, including
{{timeWindowForSize()}} method, which already uses {{windowSize}} to calculate
proper {{TimeWindow}}.
So, shouldn't we just remove {{WindowedDeserializer}}?
> Correctly calculate the window end timestamp after read from state stores
> -------------------------------------------------------------------------
>
> Key: KAFKA-4468
> URL: https://issues.apache.org/jira/browse/KAFKA-4468
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Reporter: Guozhang Wang
> Labels: architecture
>
> When storing the WindowedStore on the persistent KV store, we only use the
> start timestamp of the window as part of the combo-key as (start-timestamp,
> key). The reason that we do not add the end-timestamp as well is that we can
> always calculate it from the start timestamp + window_length, and hence we
> can save 8 bytes per key on the persistent KV store.
> However, after read it (via {{WindowedDeserializer}}) we do not set its end
> timestamp correctly but just read it as an {{UnlimitedWindow}}. We should fix
> this by calculating its end timestamp as mentioned above.
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