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https://issues.apache.org/jira/browse/HBASE-5875?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13398481#comment-13398481
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ramkrishna.s.vasudevan commented on HBASE-5875:
-----------------------------------------------
@Devs
{code}
+ // Make sure a -ROOT- location is set.
+ if (!isRootLocation()) return false;
+ // This guarantees that the transition assigning -ROOT- has completed
+ this.assignmentManager.waitForAssignment(HRegionInfo.ROOT_REGIONINFO);
+ assigned++;
{code}
and
{code}
+ // Wait until META region added to region server onlineRegions. See
HBASE-5875.
+ enableSSHandWaitForMeta();
+ assigned++;
{code}
This will ensure that we wait for ROOT and META. Now as HBASE-5918 has gone
in, if any RS goes down inbetween root and META assignment SSH will also be
triggered.
The main intention in this patch is to avoid
{code}
splitLogAndExpireIfOnline(currentRootServer);
....
splitLogAndExpireIfOnline(currentMetaServer);
{code}
because the above code in case of ROOT and META in rit was removing the current
active server thinking it as dead in case the ROOT or META is not yet online on
RS.
> Process RIT and Master restart may remove an online server considering it as
> a dead server
> ------------------------------------------------------------------------------------------
>
> Key: HBASE-5875
> URL: https://issues.apache.org/jira/browse/HBASE-5875
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.92.1
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Fix For: 0.94.1
>
> Attachments: HBASE-5875.patch, HBASE-5875_0.94.patch,
> HBASE-5875_0.94_1.patch, HBASE-5875_trunk.patch, HBASE-5875v2.patch
>
>
> If on master restart it finds the ROOT/META to be in RIT state, master tries
> to assign the ROOT region through ProcessRIT.
> Master will trigger the assignment and next will try to verify the Root
> Region Location.
> Root region location verification is done seeing if the RS has the region in
> its online list.
> If the master triggered assignment has not yet been completed in RS then the
> verify root region location will fail.
> Because it failed
> {code}
> splitLogAndExpireIfOnline(currentRootServer);
> {code}
> we do split log and also remove the server from online server list. Ideally
> here there is nothing to do in splitlog as no region server was restarted.
> So master, though the server is online, master just invalidates the region
> server.
> In a special case, if i have only one RS then my cluster will become non
> operative.
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