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From "Kihwal Lee (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HDFS-4186) logSync() is called with the write lock held while releasing lease
Date Wed, 14 Nov 2012 22:30:13 GMT

     [ https://issues.apache.org/jira/browse/HDFS-4186?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Kihwal Lee updated HDFS-4186:

    Attachment: hdfs-4186-trunk-inaccurate-batched-sync-count.patch

The new patches are without the extra thread local variable. The new tracking in lease monitor
should make the error in batched syncs count low by calling logSync() only when necessary.
> 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-branch-0.23-inaccurate-batched-sync-count.patch, hdfs-4186-trunk-inaccurate-batched-sync-count.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.

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