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https://issues.apache.org/jira/browse/KAFKA-5172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16000278#comment-16000278
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ASF GitHub Bot commented on KAFKA-5172:
---------------------------------------
Github user asfgit closed the pull request at:
https://github.com/apache/kafka/pull/2972
> CachingSessionStore doesn't fetchPrevious correctly.
> ----------------------------------------------------
>
> Key: KAFKA-5172
> URL: https://issues.apache.org/jira/browse/KAFKA-5172
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Reporter: Kyle Winkelman
> Assignee: Kyle Winkelman
> Fix For: 0.11.0.0
>
>
> When using KStreamSessionWindowAggregate by calling
> KGroupedStream#aggregate() a CachingSessionStore is created.
> This causes the following chain of method calls when a new record that
> requires removing others from the store appear:
> KStreamSessionWindowAggregate
> CachingSessionStore.remove(Windowed<K>)
> CachingSessionStore.put(Windowed<K>, V)
> ThreadCache.put(String, Bytes *containing Windowed<K> info*, LRUCacheEntry)
> ThreadCache.maybeEvict(String)
> NamedCache.evict()
> NamedCache.flush(LRUNode *containing Bytes and LRUCacheEntry from
> ThreadCache#put*)
> DirtyEntryFlushListener *defined in CachingSessionStore line 80*
> .apply(ThreadCache.DirtyEntry *containing Bytes and LRUCacheEntry from
> ThreadCache#put*)
> CachingSessionStore.putAndMaybeForward(ThreadCache.DirtyEntry *containing
> Bytes and LRUCacheEntry from ThreadCache#put*, InternalProcessorContext)
> CachingSessionStore.fetchPrevious(Bytes *containing Windowed<K> info*)
> RocksDBSessionStore.fetch(Bytes *containing Windowed<K> info*)
> RocksDBSessionStore.findSessions *on line 48* (Bytes *containing Windowed<K>
> info*, 0, Long.MAX_VALUE)
> MeteredSegmentedByteStore.fetch(Bytes *containing Windowed<K> info*, 0,
> Long.MAX_VALUE)
> ChangeLoggingSegmentedByteStore.fetch(Bytes *containing Windowed<K> info*, 0,
> Long.MAX_VALUE)
> RocksDBSegmentedBytesStore.fetch(Bytes *containing Windowed<K> info*, 0,
> Long.MAX_VALUE)
> SessionKeySchema.lower/upperRange(Bytes *containing Windowed<K> info*, Long)
> ****** in this method the already Windowed<K> gets Windowed again *****
> The point of showing all this is to point out that the windowed gets windowed
> and because it passes the 0, Long.MAX_VALUE it searches for a strange key and
> searches all times for it. I think the fetchPrevious method of
> CachingSessionStore should be changed to call the
> byteStores.findSessions(Bytes.wrap(serdes.rawKey(key.key())),
> key.window().start(), key.window().end()).
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