Github user NicoK commented on a diff in the pull request:
https://github.com/apache/flink/pull/4559#discussion_r157544794
--- 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 --
I'm not quite sure the latter two methods should be in `ResultSubpartition`
now since they are quite internal. `increaseBuffersInBacklog()` is only called
by `PipelinedSubpartition` and `SpillableSubpartition`.
`decreaseBuffersInBacklog()` is (additionally) only by spilled/spillable
subpartition views and therefore could be package-private in
`SpillableSubpartition` only.
---
