Github user aljoscha commented on a diff in the pull request:
https://github.com/apache/flink/pull/5230#discussion_r163841958
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/state/BackendWritableBroadcastState.java
---
@@ -0,0 +1,42 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.runtime.state;
+
+import org.apache.flink.api.common.state.BroadcastState;
+import org.apache.flink.core.fs.FSDataOutputStream;
+
+import java.io.IOException;
+
+/**
+ * An interface with methods related to the interplay between the {@link
BroadcastState}
+ * and the {@link OperatorStateBackend}.
+ *
+ * @param <K> The key type of the elements in the {@link BroadcastState}.
+ * @param <V> The value type of the elements in the {@link BroadcastState}.
+ */
+public interface BackendWritableBroadcastState<K, V> extends
BroadcastState<K, V> {
+
+ BackendWritableBroadcastState<K, V> deepCopy();
+
+ long[] write(FSDataOutputStream out) throws IOException;
--- End diff --
Why does the write method return all the partition offsets? Are they ever
used for anything? I think this might be leftover from `PartitionableListState`.
---
