Github user zhijiangW commented on a diff in the pull request: https://github.com/apache/flink/pull/4559#discussion_r157686388 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/io/network/partition/ResultSubpartition.java --- @@ -99,6 +82,23 @@ protected Throwable getFailureCause() { abstract public boolean isReleased(); + /** + * Gets the number of non-event buffers in this subpartition. + */ + abstract public int getBuffersInBacklog(); + + /** + * Decreases the number of non-event buffers by one after fetching a non-event + * buffer from this subpartition. + */ + abstract public void decreaseBuffersInBacklog(Buffer buffer); + + /** + * Increases the number of non-event buffers by one after adding a non-event + * buffer into this subpartition. + */ + abstract public void increaseBuffersInBacklog(Buffer buffer); --- End diff -- The current `parent` in `SpilledSubpartitionView` is `ResultSubpartition` not `SpillableSubpartition`, after replacing the `ResultSubpartition` by `SpillableSubpartition`, we can make these methods package-private as you suggest. I will do that.
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