[GitHub] [kafka] vvcephei commented on pull request #9020: KAFKA-10271 Performance degradation while fetching a key from a single partition

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vvcephei commented on pull request #9020:
URL: https://github.com/apache/kafka/pull/9020#issuecomment-658432973


   Hi @dima5rr , thanks for the PR! I was looking into the context of this ticket and noticed that we're essentially just duplicating here the logic in `org.apache.kafka.streams.state.internals.QueryableStoreProvider#getStore`, which also loops over all stores of all providers as a sanity check before even returning the WrappingStoreProvider, which will loop over all stores of all providers _again_ before returning any results.
   
   Anecdotally, I think that most people would actually just query immediately and then discard their store reference, for example like `value = kafkaStreams.store("storeName", partition=2).get("key")`. In that case, this double-iteration is pretty expensive, and the up-front sanity check doesn't seem to provide any value.
   
   What do you think about removing the loop https://github.com/apache/kafka/blob/f699bd98c14e31f07c5a3f6ba9ce2c4b441e7fdb/streams/src/main/java/org/apache/kafka/streams/state/internals/QueryableStoreProvider.java#L59-L77 in favor of the one in here?
   
   Of course, the short-circuit you're providing here is valuable in any case.
   
   Thanks!
   -John


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