nileshkumar3 commented on code in PR #21840: URL: https://github.com/apache/kafka/pull/21840#discussion_r3223467620
########## docs/streams/upgrade-guide.md: ########## @@ -75,6 +75,18 @@ Kafka Streams now allows to purge local state directories and checkpoint files d Kafka Streams now persists state store changelog offsets inside each state store rather than in a single per-task `.checkpoint` file ([KIP-1035](https://cwiki.apache.org/confluence/display/KAFKA/KIP-1035%3A+StateStore+managed+changelog+offsets)). This is an internal infrastructure change and is transparent to most users — existing per-task `.checkpoint` files are migrated automatically on first startup, and no application or operator action is required. EOS crash behavior is unchanged in 4.3: state stores are still wiped and fully restored from the changelog. KIP-1035 is a prerequisite for [KIP-892: Transactional Semantics for StateStores](https://cwiki.apache.org/confluence/display/KAFKA/KIP-892%3A+Transactional+Semantics+for+StateStores), which will use these per-store offsets to make EOS state writes transactional and skip the full restore. Authors of custom `StateStore` implementations may opt-in to managing their own offsets via `managesOffsets()`, `commit(Map<TopicPartition, Long>)`, and `committedOffset(TopicPartition)`; see KIP-1035 for the API. For downgrade implications, see [Notable compatibility changes in past releases](#notable-compatibility-changes-in-past-releases). +### Header-aware state stores for the Processor API (KIP-1271) {#kip-1271-headers-aware-stores} + +Kafka Streams adds **header-aware** state stores. Opt in with the new `Stores` suppliers whose names end with `WithHeaders` and the matching `StoreBuilder` factories—for example `persistentTimestampedKeyValueStoreWithHeaders` with `timestampedKeyValueStoreBuilderWithHeaders`, `persistentTimestampedWindowStoreWithHeaders` with `timestampedWindowStoreWithHeadersBuilder`, and `persistentSessionStoreWithHeaders` with `sessionStoreBuilderWithHeaders`. See the [Processor API state store documentation](developer-guide/processor-api.html#headers-in-state-stores). Review Comment: changed the long sentence into 3 pairs. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
