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https://issues.apache.org/jira/browse/HDFS-12278?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16120620#comment-16120620
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Rushabh S Shah commented on HDFS-12278:
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{{TestDFSStripedOutputStreamWithFailure150}} and
{{TestDFSStripedOutputStreamWithFailure080}} are well known flaky tests.
Both have failed number of times. I ran 4 times each test. Fails with a
probability of 50%
{{TestUnderReplicatedBlocks#testSetRepIncWithUnderReplicatedBlocks}} is timing
out. Tracked via HDFS-9243.
There are no new tests since all the existing test covers the correctness.
Will attach a branch-2.8 patch soon.
> LeaseManager operations are inefficient in 2.8.
> -----------------------------------------------
>
> Key: HDFS-12278
> URL: https://issues.apache.org/jira/browse/HDFS-12278
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 2.8.0
> Reporter: Rushabh S Shah
> Assignee: Rushabh S Shah
> Priority: Blocker
> Attachments: HDFS-12278.patch
>
>
> After HDFS-6757, LeaseManager #removeLease became expensive.
> HDFS-6757 changed the {{sortedLeases}} object from TreeSet to PriorityQueue.
> Previously the {{remove(Object)}} operation from {{sortedLeases}} was {{O(log
> n)}} but after the change it became {{O( n)}} since it has to find the object
> first.
> Recently we had an incident in one of our production cluster just hours after
> we upgraded from 2.7 to 2.8
> The {{sortledLeases}} object had approximately 100,000 items within it.
> While removing the lease, it will acquire the LeaseManager lock and that will
> slow down the lookup of lease also.
> HDFS-6757 is a good improvement which replaced the path by inode id.
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