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https://issues.apache.org/jira/browse/HBASE-25596?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17360612#comment-17360612
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Sandeep Pal commented on HBASE-25596:
-------------------------------------
Sure, if this is true "we will never throw EOFException to upper layer, so the
problem you described here should not happen", then it make sense that there
will be no unshipped batch. I was not aware of this. Let me check the code once
more carefully and I will create a PR to revert it. Thanks [~zhangduo]
> Fix NPE in ReplicationSourceManager as well as avoid permanently unreplicated
> data due to EOFException from WAL
> ---------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-25596
> URL: https://issues.apache.org/jira/browse/HBASE-25596
> Project: HBase
> Issue Type: Bug
> Reporter: Sandeep Pal
> Assignee: Sandeep Pal
> Priority: Critical
> Fix For: 3.0.0-alpha-1, 1.7.0, 2.5.0, 2.4.2
>
>
> There seems to be a major issue with how we handle the EOF exception from
> WALEntryStream.
> Problem:
> When we see EOFException, we try to handle it and remove it from the log
> queue, but we never try to ship the existing batch of entries. *This is a
> permanent data loss in replication.*
>
> Secondly, we do not stop the reader on encountering the EOFException and thus
> if EOFException was on the last WAL, we still try to process the WALEntry
> stream and ship the empty batch with lastWALPath set to null. This is the
> reason of NPE as below which *crash* the region server.
> {code:java}
> 2021-02-16 15:33:21,293 ERROR [,60020,1613262147968]
> regionserver.ReplicationSource - Unexpected exception in
> ReplicationSourceWorkerThread,
> currentPath=nulljava.lang.NullPointerExceptionat
> org.apache.hadoop.hbase.replication.regionserver.ReplicationSourceManager.logPositionAndCleanOldLogs(ReplicationSourceManager.java:193)at
>
> org.apache.hadoop.hbase.replication.regionserver.ReplicationSource$ReplicationSourceShipperThread.updateLogPosition(ReplicationSource.java:831)at
>
> org.apache.hadoop.hbase.replication.regionserver.ReplicationSource$ReplicationSourceShipperThread.shipEdits(ReplicationSource.java:746)at
>
> org.apache.hadoop.hbase.replication.regionserver.ReplicationSource$ReplicationSourceShipperThread.run(ReplicationSource.java:650)2021-02-16
> 15:33:21,294 INFO [,60020,1613262147968] regionserver.HRegionServer -
> STOPPED: Unexpected exception in ReplicationSourceWorkerThread
> {code}
>
>
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