[GitHub] flink pull request #3001: [FLINK-4821] [kinesis] Implement rescalable non-pa...

[tzulitai <gi...@git.apache.org>]

Github user tzulitai commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3001#discussion_r112122128
  
    --- Diff: flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/FlinkKinesisConsumer.java ---
    @@ -267,38 +293,84 @@ public void close() throws Exception {
     	// ------------------------------------------------------------------------
     
     	@Override
    -	public HashMap<KinesisStreamShard, SequenceNumber> snapshotState(long checkpointId, long checkpointTimestamp) throws Exception {
    +	public void snapshotState(FunctionSnapshotContext context) throws Exception {
     		if (lastStateSnapshot == null) {
     			LOG.debug("snapshotState() requested on not yet opened source; returning null.");
    -			return null;
    -		}
    -
    -		if (fetcher == null) {
    +		} else if (fetcher == null) {
     			LOG.debug("snapshotState() requested on not yet running source; returning null.");
    -			return null;
    -		}
    -
    -		if (!running) {
    +		} else if (!running) {
     			LOG.debug("snapshotState() called on closed source; returning null.");
    -			return null;
    +		} else {
    +			if (LOG.isDebugEnabled()) {
    +				LOG.debug("Snapshotting state ...");
    +			}
    +
    +			offsetsStateForCheckpoint.clear();
    +			lastStateSnapshot = fetcher.snapshotState();
    +
    +			if (LOG.isDebugEnabled()) {
    +				LOG.debug("Snapshotted state, last processed sequence numbers: {}, checkpoint id: {}, timestamp: {}",
    +					lastStateSnapshot.toString(), context.getCheckpointId(), context.getCheckpointTimestamp());
    +			}
    +
    +			for (Map.Entry<KinesisStreamShard, SequenceNumber> entry : lastStateSnapshot.entrySet()) {
    +				offsetsStateForCheckpoint.add(Tuple2.of(entry.getKey(), entry.getValue()));
    +			}
     		}
    +	}
     
    -		if (LOG.isDebugEnabled()) {
    -			LOG.debug("Snapshotting state ...");
    +	@Override
    +	public void initializeState(FunctionInitializationContext context) throws Exception {
    +		TypeInformation<Tuple2<KinesisStreamShard, SequenceNumber>> tuple = new TupleTypeInfo<>(
    +			TypeInformation.of(KinesisStreamShard.class),
    +			TypeInformation.of(SequenceNumber.class)
    +		);
    +
    +		offsetsStateForCheckpoint = context.getOperatorStateStore().getUnionListState(
    +			new ListStateDescriptor<>(DefaultOperatorStateBackend.DEFAULT_OPERATOR_STATE_NAME, tuple));
    +
    +		if (context.isRestored()) {
    +			if (sequenceNumsToRestore == null) {
    +				sequenceNumsToRestore = new HashMap<>();
    +				for (Tuple2<KinesisStreamShard, SequenceNumber> kinesisOffset : offsetsStateForCheckpoint.get()) {
    +					sequenceNumsToRestore.put(kinesisOffset.f0, kinesisOffset.f1);
    +				}
    +
    +				LOG.info("Setting restore state in the FlinkKinesisConsumer.");
    +				if (LOG.isDebugEnabled()) {
    +					LOG.debug("Using the following offsets: {}", sequenceNumsToRestore);
    +				}
    +			} else if (sequenceNumsToRestore.isEmpty()) {
    +				sequenceNumsToRestore = null;
    +			}
    +		} else {
    +			LOG.info("No restore state for FlinkKinesisConsumer.");
     		}
    +	}
     
    -		lastStateSnapshot = fetcher.snapshotState();
    +	@Override
    +	public void restoreState(HashMap<KinesisStreamShard, SequenceNumber> restoredState) throws Exception {
    +		LOG.info("{} (taskIdx={}) restoring offsets from an older version.",
    --- End diff --
    
    I think the other log messages follow a different format then this.
    The others do something like `Subtask {} is restoring offset from an older version`?


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