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From "Kihwal Lee (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HDFS-5346) Avoid unnecessary call to getNumLiveDataNodes() for each block during IBR processing
Date Wed, 16 Oct 2013 21:02:43 GMT

     [ https://issues.apache.org/jira/browse/HDFS-5346?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Kihwal Lee updated HDFS-5346:
-----------------------------

    Description: 
When initial block reports are being processed, checkMode() is called from incrementSafeBlockCount().
This causes the replication queues to be initialized in the middle of processing a block report
in the IBR processing mode. If there are many block reports waiting to be processed, SafeModeMonitor
won't be able to make name node leave the safe mode soon. It appears that the block report
processing speed degrades considerably during this time. 

Update: The main issue can be resolved by config. The other issue of calling 

  was:When initial block reports are being processed, checkMode() is called from incrementSafeBlockCount().
This causes the replication queues to be initialized in the middle of processing a block report
in the IBR processing mode. If there are many block reports waiting to be processed, SafeModeMonitor
won't be able to make name node leave the safe mode soon. It appears that the block report
processing speed degrades considerably during this time. 


> Avoid unnecessary call to getNumLiveDataNodes() for each block during IBR processing
> ------------------------------------------------------------------------------------
>
>                 Key: HDFS-5346
>                 URL: https://issues.apache.org/jira/browse/HDFS-5346
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode, performance
>    Affects Versions: 0.23.9, 2.3.0
>            Reporter: Kihwal Lee
>            Assignee: Ravi Prakash
>             Fix For: 2.3.0, 0.23.10
>
>         Attachments: HDFS-5346.branch-23.patch, HDFS-5346.branch-23.patch, HDFS-5346.patch,
HDFS-5346.patch, HDFS-5346.patch
>
>
> When initial block reports are being processed, checkMode() is called from incrementSafeBlockCount().
This causes the replication queues to be initialized in the middle of processing a block report
in the IBR processing mode. If there are many block reports waiting to be processed, SafeModeMonitor
won't be able to make name node leave the safe mode soon. It appears that the block report
processing speed degrades considerably during this time. 
> Update: The main issue can be resolved by config. The other issue of calling 



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