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Posted to issues@flink.apache.org by "Piotr Nowojski (JIRA)" <ji...@apache.org> on 2019/06/21 07:12:01 UTC
[jira] [Comment Edited] (FLINK-12912) Incorrect handling of
task.checkpoint.alignment.max-size when one checkpoint subsumes another one
[ https://issues.apache.org/jira/browse/FLINK-12912?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16869254#comment-16869254 ]
Piotr Nowojski edited comment on FLINK-12912 at 6/21/19 7:11 AM:
-----------------------------------------------------------------
I couldn't fix the code easily, so I'm stopping progress on trying to fix that.
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}}.
was (Author: pnowojski):
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
> 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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