[
https://issues.apache.org/jira/browse/HDFS-4186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13496911#comment-13496911
]
Todd Lipcon commented on HDFS-4186:
-----------------------------------
Hey Kihwal. Can you explain why the new ThreadLocal is necessary?
Without the new ThreadLocal, the thread would just have a too-low txid, which
would already be synced from some previous call on the same IPC handler. So the
logSync would already end up a no-op, given the synced txid already will be
higher than this point.
> logSync() is called with the write lock held while releasing lease
> ------------------------------------------------------------------
>
> Key: HDFS-4186
> URL: https://issues.apache.org/jira/browse/HDFS-4186
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: name-node
> Affects Versions: 0.23.4, 2.0.2-alpha
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Priority: Critical
> Attachments: hdfs-4186-trunk.patch
>
>
> As pointed out in HDFS-4138, when the lease monitor calls
> internalReleaseLease(), it acquires the namespace write lock. Inside
> internalReleaseLease(), if a block recovery is needed, the lease is
> reassigned to the namenode itself and this is logged & synced in
> logReassignLease().
> Since this is done while the write lock is held, log syncing is blocked. When
> a large number of leases are expired and blocks are recovered, namenode can
> slow down.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
