Handling read failures during recovery - when HMaster calls Namenode recovery,
recovery may be a failure leading to read failure while splitting logs
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Key: HBASE-4177
URL: https://issues.apache.org/jira/browse/HBASE-4177
Project: HBase
Issue Type: Bug
Components: master
Reporter: ramkrishna.s.vasudevan
Assignee: ramkrishna.s.vasudevan
As per the mailing thread with the heading
'Handling read failures during recovery' we found this problem.
As part of split Logs the HMaster calls Namenode recovery. The recovery is an
asynchronous process.
In HDFS
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Even though client is getting the updated block info from Namenode on first
read failure, client is discarding the new info and using the old info only
to retrieve the data from datanode. So, all the read
retries are failing. [Method parameter reassignment - Not reflected in
caller].
In HBASE
=======
In HMaster code we tend to wait for 1sec. But if the recovery had some
failure then split log may not happen and may lead to dataloss.
So may be we need to decide upon the actual delay that needs to be introduced
once Hmaster calls NN recovery.
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