GlobalStateUpdateTask — The Default GlobalStateMaintainer

GlobalStateUpdateTask is the one and only GlobalStateMaintainer that…FIXME

GlobalStateUpdateTask is created exclusively when GlobalStreamThread is requested to initialize (and creates a StateConsumer).

GlobalStateUpdateTask keeps track of the offsets of the records (by the topics and the partitions) that have already been processed. The offsets are then flushed to the global store when requested.

GlobalStateUpdateTask keeps track of the deserializers for…FIXME

Initializing — `initialize` Method

Map<TopicPartition, Long> initialize()

Note	`initialize` is part of GlobalStateMaintainer Contract to…FIXME.

initialize…FIXME

`update` Method

void update(final ConsumerRecord<byte[], byte[]> record)

Note	`update` is part of GlobalStateMaintainer Contract to…FIXME.

update looks up the RecordDeserializer for the topic (of the record) in the deserializers internal registry.

Note	`RecordDeserializer` is the metadata of a SourceNode that knows how to deserialize a raw record in a given `ProcessorContext`.

update then uses the RecordDeserializer to deserialize the record (to the proper types of the key and the value).

When the record has been successfully deserialized, update does the following:

Creates a ProcessorRecordContext for the deserialized record
Requests InternalProcessorContext to use the record context
Requests InternalProcessorContext to use the source node of the RecordDeserializer
Requests the SourceNode (of the deserialized record) to process the deserialized record

In the end, update saves the topic and the partition of the record with the offset in the offsets internal registry.

Flushing State Stores — `flushState` Method

void flushState()

Note	`flushState` is part of GlobalStateMaintainer Contract to…FIXME.

flushState requests GlobalStateManager to flush followed by checkpointing the offsets.

Closing State Manager — `close` Method

void close() throws IOException

Note	`close` is part of StateManager Contract to…FIXME.

close simply requests GlobalStateManager to close (passing on the offsets).

Creating GlobalStateUpdateTask Instance

GlobalStateUpdateTask takes the following when created:

ProcessorTopology
InternalProcessorContext
GlobalStateManager
DeserializationExceptionHandler
LogContext

GlobalStateUpdateTask initializes the offsets and deserializers internal registries.

`initTopology` Internal Method

void initTopology()

initTopology…FIXME

Note	`initTopology` is used exclusively when `GlobalStateUpdateTask` is requested to initialize.

GlobalStateUpdateTask