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https://issues.apache.org/jira/browse/FLINK-12912?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16869254#comment-16869254
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Piotr Nowojski commented on FLINK-12912:
----------------------------------------
After implementing https://issues.apache.org/jira/browse/FLINK-12777 the bugged
code has moved fully to {{BufferStorage}} class and is visible via
{{BufferStorage#isFull()}} method. For example following sequence doesn't work
{code:java}
bufferStorage = new BufferStorageXYZ(maxSizeLimit = PAGE_SIZE *
7);
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
bufferStorage.rollOver();
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
bufferStorage.rollOver();
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
assertFalse(bufferStorage.isFull());
bufferStorage.add(generateRandomBuffer(PAGE_SIZE));
assertTrue(bufferStorage.isFull());
{code}
Take a look at
{{org.apache.flink.streaming.runtime.io.LinkedBufferStorageTest#testRolledIsFull}}.
> Incorrect handling of task.checkpoint.alignment.max-size when one checkpoint
> subsumes another one
> -------------------------------------------------------------------------------------------------
>
> Key: FLINK-12912
> URL: https://issues.apache.org/jira/browse/FLINK-12912
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Network
> Affects Versions: 1.6.4, 1.7.2, 1.8.0
> Reporter: Piotr Nowojski
> Assignee: Piotr Nowojski
> Priority: Major
>
> {{BarrierBuffer#numQueuedBytes}} which is used to evaluate {{
> task.checkpoint.alignment.max-size}} limit, is not correctly handled if one
> checkpoint subsumes another one.
> The max size limit is checked against a sum of {{numQueuedBytes}} and
> {{bufferBlocker.getBytesBlocked()}}. The {{getBytesBlocked}} keeps tracks of
> the alignment size of the only most latest checkpoint. The bug is
> {{BarrierBuffer#releaseBlocksAndResetBarriers()}} method, where while
> handling first subsumed checkpoint in the branch:
> {code:java}
> if (currentBuffered == null) {
> // common case: no more buffered data
> currentBuffered =
> bufferBlocker.rollOverReusingResources();
> if (currentBuffered != null) {
> currentBuffered.open();
> }
> }
> {code}
> we clear the {{bufferBlocker.getBytesBlocked()}} counter, while we do not
> update {{numQueuedBytes}} counter.
> For example when first checkpoint approached to 99.9% of max alignment size
> when it was subsumed, due to this bug calculated alignment size drops to 0
> bytes. For subsequent subsumed checkpoints {{numQueuedBytes}} is correctly
> updated.
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