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https://issues.apache.org/jira/browse/HBASE-20723?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16513019#comment-16513019
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Zach York commented on HBASE-20723:
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[~yuzhih...@gmail.com] I did reproduce the issue on my side as well. Let me
review your patch as well.
I think going forward we need two things to prevent something like this
happening again:
# Tests that utilize hbase.wal.dir (on a different FS and path) to validate
that edits are able to be replayed and logs are split from a user level (put,
kill RS, restart RS, check to ensure edit is present in table).
# Improve on this log messaging around here. There should be some indication
of the number of records replayed or something as the current logging is easy
to miss... Considering this log means that edits won't be applied for that
region, this should at the very least be a WARN to indicate something
potentially wrong happened.
> WALSplitter uses the rootDir, which is walDir, as the tableDir root path.
> -------------------------------------------------------------------------
>
> Key: HBASE-20723
> URL: https://issues.apache.org/jira/browse/HBASE-20723
> Project: HBase
> Issue Type: Bug
> Components: hbase
> Affects Versions: 1.1.2
> Reporter: Rohan Pednekar
> Assignee: Ted Yu
> Priority: Major
> Attachments: 20723.v1.txt, 20723.v2.txt, 20723.v3.txt, 20723.v4.txt,
> 20723.v5.txt, 20723.v5.txt, 20723.v6.txt, logs.zip
>
>
> This is an Azure HDInsight HBase cluster with HDP 2.6. and HBase
> 1.1.2.2.6.3.2-14
> By default the underlying data is going to wasb://xxxxx@yyyyy/hbase
> I tried to move WAL folders to HDFS, which is the SSD mounted on each VM at
> /mnt.
> hbase.wal.dir= hdfs://mycluster/walontest
> hbase.wal.dir.perms=700
> hbase.rootdir.perms=700
> hbase.rootdir=
> wasb://XYZ[@hbaseperf.core.net|mailto:duohbase5ds...@duohbaseperf.blob.core.windows.net]/hbase
> Procedure to reproduce this issue:
> 1. create a table in hbase shell
> 2. insert a row in hbase shell
> 3. reboot the VM which hosts that region
> 4. scan the table in hbase shell and it is empty
> Looking at the region server logs:
> {code:java}
> 2018-06-12 22:08:40,455 INFO [RS_LOG_REPLAY_OPS-wn2-duohba:16020-0-Writer-1]
> wal.WALSplitter: This region's directory doesn't exist:
> hdfs://mycluster/walontest/data/default/tb1/b7fd7db5694eb71190955292b3ff7648.
> It is very likely that it was already split so it's safe to discard those
> edits.
> {code}
> The log split/replay ignored actual WAL due to WALSplitter is looking for the
> region directory in the hbase.wal.dir we specified rather than the
> hbase.rootdir.
> Looking at the source code,
> https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALSplitter.java
> it uses the rootDir, which is walDir, as the tableDir root path.
> So if we use HBASE-17437, waldir and hbase rootdir are in different path or
> even in different filesystem, then the #5 uses walDir as tableDir is
> apparently wrong.
> CC: [~zyork], [~yuzhih...@gmail.com] Attached the logs for quick review.
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