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https://issues.apache.org/jira/browse/HBASE-20792?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16526990#comment-16526990
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Duo Zhang commented on HBASE-20792:
-----------------------------------
Looked at the log above, I think there maybe a corner case that we haven't
handle it correctly. When closing a region, we will do a flush, and it will
also increase the sequence id as we need to write a flush marker, and this
value will be persist to the store file. And when closing, we will also write a
close marker and update the max sequence id file.
And here, for [~elserj]'s scenario, we do not write anything into the region,
so there will be no flush, so we can not persist the sequence id to store file.
And maybe the checks around the updating max sequence id file also prevents the
updating, and since this is a normal close/reopen, we will not replay the wals,
so the close region marker will not be considered either, then the openSeqNum
will remain the same.
Let me try it locally to see if I can find the problem.
> info:servername and info:sn inconsistent for OPEN region
> --------------------------------------------------------
>
> Key: HBASE-20792
> URL: https://issues.apache.org/jira/browse/HBASE-20792
> Project: HBase
> Issue Type: Bug
> Components: Region Assignment
> Reporter: Josh Elser
> Assignee: Josh Elser
> Priority: Blocker
> Fix For: 3.0.0, 2.1.0, 2.0.2, 2.2.0
>
> Attachments: HBASE-20792.patch, TestRegionMoveAndAbandon.java,
> hbase-hbase-master-ctr-e138-1518143905142-380753-01-000004.hwx.site.log
>
>
> Next problem we've run into after HBASE-20752 and HBASE-20708
> After a rolling restart of a cluster, we'll see situations where a collection
> of regions will simply not be assigned out to the RS. I was able to reproduce
> this my mimic the restart patterns our tests do internally (ignore whether
> this is the best way to restart nodes for now :)). The general pattern is
> this:
> {code:java}
> for rs in regionservers:
> stop(server, rs, RS)
> for master in masters:
> stop(server, master, MASTER)
> sleep(15)
> for master in masters:
> start(server, master, MASTER)
> for rs in regionservers:
> start(server, rs, RS){code}
> Looking at meta, we can see why the Master is ignoring some regions:
> {noformat}
> test
> column=table:state, timestamp=1529871718998, value=\x08\x00
> test,,1529871718122.0297f680df6dc0166a44f9536346268e.
> column=info:regioninfo, timestamp=1529967103390, value={ENCODED =>
> 0297f680df6dc0166a44f9536346268e, NAME =>
> 'test,,1529871718122.0297f680df6dc0166a44f9536346268e.', STARTKEY
> => '', ENDKEY =>
> ''}
> test,,1529871718122.0297f680df6dc0166a44f9536346268e.
> column=info:seqnumDuringOpen, timestamp=1529967103390,
> value=\x00\x00\x00\x00\x00\x00\x00*
> test,,1529871718122.0297f680df6dc0166a44f9536346268e.
> column=info:server, timestamp=1529967103390,
> value=ctr-e138-1518143905142-378097-02-000012.hwx.site:16020
> test,,1529871718122.0297f680df6dc0166a44f9536346268e.
> column=info:serverstartcode, timestamp=1529967103390, value=1529966776248
> test,,1529871718122.0297f680df6dc0166a44f9536346268e. column=info:sn,
> timestamp=1529967096482,
> value=ctr-e138-1518143905142-378097-02-000006.hwx.site,16020,1529966755170
> test,,1529871718122.0297f680df6dc0166a44f9536346268e.
> column=info:state, timestamp=1529967103390, value=OPEN{noformat}
> The region is marked as {{OPEN}}. The master doesn't know any better.
> However, the interesting bit is that {{info:server}} and {{info:sn}} are
> inconsistent (which, according to the javadoc should not be possible for an
> {{OPEN}} region).{{}}
> This doesn't happen every time, but I caught it yesterday on the 2nd or 3rd
> attempt, so I'm hopeful it's not a bear to repro.
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