[jira] [Created] (FLINK-12912) Incorrect handling of task.checkpoint.alignment.max-size when one checkpoint subsumes another one

["Piotr Nowojski (JIRA)" <ji...@apache.org>]

Piotr Nowojski created FLINK-12912:
--------------------------------------

             Summary: 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: 1.8.0, 1.7.2, 1.6.4
            Reporter: Piotr Nowojski
            Assignee: Piotr Nowojski


{{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.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)