Github user GJL commented on a diff in the pull request: https://github.com/apache/flink/pull/5703#discussion_r175126334 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/rest/messages/checkpoints/CheckpointStatistics.java --- @@ -438,4 +453,58 @@ public int hashCode() { return Objects.hash(super.hashCode(), failureTimestamp, failureMessage); } } + + /** + * Statistics for a pending checkpoint. + */ + public static final class PendingCheckpointStatistics extends CheckpointStatistics { --- End diff -- `@JsonSubTypes.Type(value = CheckpointStatistics.PendingCheckpointStatistics.class, name = "in_progress")` should be added to `CheckpointStatistics` otherwise deserialization will fail.
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