Kafka Streams closing processor's state store

Question

JavaDoc description for Processor.close() in Kafka 1.0.1 says, that:

Note: Do not close any streams managed resources, like StateStores here, as they are managed by the library.

In addition, the JavaDoc description of StateStore.close() says, that:

Users only need to implement this function but should NEVER need to call this api explicitly as it will be called by the library automatically when necessary

But I've found an example in the documentation, in which a state store is being explicitly closed inside that method:

@Override
public void close() {
    // close the key-value store
    kvStore.close();
}

So, I'm kind of lost. Should I close the state store inside a Processor, or not?

Answer 1

No, you should not close the store.

The example code snippet is wrong. Thanks for pointing it out. I opened a PR to fix it: https://github.com/apache/kafka/pull/4667