[jira] [Created] (KAFKA-14864) Memory leak in KStreamWindowAggregate with ON_WINDOW_CLOSE emit strategy

["Victoria Xia (Jira)" <ji...@apache.org>]

Victoria Xia created KAFKA-14864:
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             Summary: Memory leak in KStreamWindowAggregate with ON_WINDOW_CLOSE emit strategy
                 Key: KAFKA-14864
                 URL: https://issues.apache.org/jira/browse/KAFKA-14864
             Project: Kafka
          Issue Type: Bug
          Components: streams
            Reporter: Victoria Xia
            Assignee: Victoria Xia
             Fix For: 3.5.0


The Streams DSL processor implementation for the ON_WINDOW_CLOSE emit strategy during KStream windowed aggregations opens a key-value iterator but does not call `close()` on it ([link|https://github.com/apache/kafka/blob/5afedd9ac37c4d740f47867cfd31eaed15dc542f/streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractKStreamTimeWindowAggregateProcessor.java#L203]), despite the Javadocs for the iterator making clear that users must do so in order to release resources ([link|https://github.com/apache/kafka/blob/5afedd9ac37c4d740f47867cfd31eaed15dc542f/streams/src/main/java/org/apache/kafka/streams/state/KeyValueIterator.java#L27]).  

I discovered this bug while running load testing benchmarks and noticed that some runs were sporadically hitting OOMs, so it is definitely possible to hit this in practice.



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