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https://issues.apache.org/jira/browse/FLINK-7499?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16261077#comment-16261077
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ASF GitHub Bot commented on FLINK-7499:
---------------------------------------
Github user NicoK commented on a diff in the pull request:
https://github.com/apache/flink/pull/4581#discussion_r152342531
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/io/network/partition/SpillableSubpartitionView.java
---
@@ -108,11 +108,7 @@ int releaseMemory() throws IOException {
for (int i = 0; i < numBuffers; i++) {
Buffer buffer = buffers.remove();
spilledBytes += buffer.getSize();
- try {
- spillWriter.writeBlock(buffer);
- } finally {
- buffer.recycle();
- }
+ spillWriter.writeBlock(buffer);
--- End diff --
Actually, if I see this correctly, here the original code is wrong since it
is already recycling a buffer which was added to an asynchronous file write
operation. This would lead to data corruption if the buffer is re-used in the
meanwhile, wouldn't it?!
> double buffer release in SpillableSubpartitionView
> --------------------------------------------------
>
> Key: FLINK-7499
> URL: https://issues.apache.org/jira/browse/FLINK-7499
> Project: Flink
> Issue Type: Sub-task
> Components: Network
> Affects Versions: 1.2.0, 1.1.4, 1.3.0, 1.1.5, 1.2.1, 1.2.2, 1.3.1, 1.4.0,
> 1.3.2, 1.3.3
> Reporter: Nico Kruber
> Assignee: Nico Kruber
> Priority: Blocker
>
> {{SpillableSubpartitionView#releaseMemory()}} recycles its buffers twice:
> once asynchronously after the write operation and once in
> {{SpillableSubpartitionView#releaseMemory()}} after adding the write
> operation to the queue.
> 1) if {{SpillableSubpartitionView#releaseMemory()}} hits first and the buffer
> is recycled, the memory region may already be reused despite the pending write
> 2) If, for some reason (probably only in tests like
> {{SpillableSubpartitionTest#testConsumeSpillablePartitionSpilledDuringConsume()}}?),
> the buffer is retained and to be used in parallel somewhere else it may also
> not be available anymore or contain corrupt data.
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