[GitHub] [flink] AHeise commented on a change in pull request #12353: [FLINK-17322][network] Fixes BroadcastRecordWriter overwriting memory segments on first finished BufferConsumer.

[GitBox <gi...@apache.org>]

AHeise commented on a change in pull request #12353:
URL: https://github.com/apache/flink/pull/12353#discussion_r432502570



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File path: flink-runtime/src/main/java/org/apache/flink/runtime/io/network/api/writer/BroadcastRecordWriter.java
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@@ -130,7 +132,7 @@ public BufferBuilder requestNewBufferBuilder(int targetChannel) throws IOExcepti
 
 		BufferBuilder builder = super.requestNewBufferBuilder(targetChannel);
 		if (randomTriggered) {
-			addBufferConsumer(builder.createBufferConsumer(), targetChannel);
+			addBufferConsumer(randomConsumer = builder.createBufferConsumer(), targetChannel);

Review comment:
       We have to or else the underlying buffer is not reference counted properly.
   The idea is to keep the `randomConsumer` and use `copy` to use the then updated reader index. 
   If the random event spans multiple buffers, only the last `randomConsumer` is effectively used.




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