I want to query a Kafka Streams state store based on time range. The use case is that I'll have the streams processor be scheduled every 30 seconds. During each invocation, I want to query a state store but for only the entries which are "new". I thought TimestampedKeyValueStore might help but couldn't find the right APIs to do it. Is it possible to query the state store based on time range (and with exactly-once guarantee)?
1 Answers
You cannot query a KeyValueStore base on a time range, because this does not really align to the semantics of the store. Queries are always against the key, and a TimestampeKeyValueStore stores an additional value-timestamp.
You could use a WindowedStore though: note, a windowed-store is basically also just a key-value store, however, it store a timestamp next to the key (not the value; well, there is also TimestampedWindowStore that also does both). This allows you to query time ranges.
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