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https://issues.apache.org/jira/browse/HBASE-25596?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sandeep Pal updated HBASE-25596:
--------------------------------
Description:
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$ReplicationSourceShipperThread.run(ReplicationSource.java:650)2021-02-16
15:33:21,294 INFO [,60020,1613262147968] regionserver.HRegionServer - STOPPED:
Unexpected exception in ReplicationSourceWorkerThread
{code}
was:
There seems to be a major issue with how we handle the EOF exception from
WALEntryStream.
Problem:
When we see EOFException, we try to handle it and remove it from the log queue,
but we never try to ship the existing batch of entries. *This is a permanent
data loss in replication.*
Secondly, we do not stop the reader on encountering the EOFException and thus
if EOFException was on the last WAL, we still try to process the WALEntry
stream and ship the empty batch with lastWALPath set to null. This is the
reason of NPE as below.
{code:java}
2021-02-16 15:33:21,293 ERROR [,60020,1613262147968]
regionserver.ReplicationSource - Unexpected exception in
ReplicationSourceWorkerThread, currentPath=nulljava.lang.NullPointerExceptionat
org.apache.hadoop.hbase.replication.regionserver.ReplicationSourceManager.logPositionAndCleanOldLogs(ReplicationSourceManager.java:193)at
org.apache.hadoop.hbase.replication.regionserver.ReplicationSource$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}
> 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, 2.3.5, 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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