kafka-streams-internals-ChangelogReader.adoc

ChangelogReader Internal Contract

ChangelogReader is the internal contract for changelog readers that…​FIXME

Table 1. ChangelogReader Contract

Method	Description
register	void register(StateRestorer restorer) Registers a StateRestorer (for a changelog partition) Used exclusively when ProcessorStateManager is requested to register a persistent state store (with an underlying changelog topic)
reset	void reset() Used exclusively when TaskManager is requested to suspend all (active and standby) tasks and state (when RebalanceListener is requested to handle onPartitionsRevoked event (at the beginning of consumer rebalance))
restore	Collection<TopicPartition> restore( RestoringTasks active) Restores logging-enabled state stores using the RestoringTasks Used exclusively when TaskManager is requested to updateNewAndRestoringTasks (when the owning StreamThread is requested to poll records once and process them using active stream tasks while running the main record processing loop)
restoredOffsets	Map<TopicPartition, Long> restoredOffsets() Restores offsets (for persistent state stores) Used exclusively when ProcessorStateManager is requested to checkpoint offsets

Note	StoreChangelogReader is the default and only known implementation of the ChangelogReader Contract in Kafka Streams.