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https://issues.apache.org/jira/browse/HBASE-20792?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16524567#comment-16524567
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Josh Elser commented on HBASE-20792:
------------------------------------
Ok, I have a test – (very) initial signs are pointing that HBASE-20708 might
have inadvertently removed a critical path. Running my test on branch-2.0, it
passes, but I see us getting into the same meta state:
{noformat}
2018-06-27 00:27:31,828 INFO [M:0;hw13390:60070]
assignment.RegionStateStore(122): Load hbase:meta entry
region=fc00bdddfdec0ebe72132de4197c3247, regionState=OPEN,
lastHost=hw13390.local,60048,1530073629090,
regionLocation=hw13390.local,60046,1530073629030, openSeqNum=14
2018-06-27 00:27:31,828 INFO [M:0;hw13390:60070]
assignment.AssignmentManager(1211): Number of RegionServers=2
2018-06-27 00:27:31,828 INFO [M:0;hw13390:60070]
assignment.AssignmentManager(1331): KILL
RegionServer=hw13390.local,60046,1530073629030 hosting regions but not online.
{noformat}
That last {{KILL}} log message is what saves our bacon. This triggers the
region to get reassigned via an SCP that otherwise doesn't happen. Haven't
looked further other than to say that this logic was shuffled around as a part
of that. I'll throw up my test case if anyone would like to mess around with it.
> 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: 2.0.2
>
> Attachments:
> 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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