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https://issues.apache.org/jira/browse/HBASE-2235?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12836078#action_12836078
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stack commented on HBASE-2235:
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@ Kannan For sure, lets do something in 0.20. I think metascanner when it
runs can check an offlined region. If its not followed by two daughters -- it
has the necessary info as columns splitA and splitB -- it can add them. Let me
take a closer look. Will report back (Am on something else this afternoon).
Having all in the one row is a bit radical. Gets and puts would each take out
a row lock. I think this might slow down all .META. lookups. We also have a
mechanism for getting the row closest to the asked for one. Its used for
figuring out which region a row sits in. This would have to be recast if all
was in the one row.
> Mechanism that would not have -ROOT- and .META. on same server caused failed
> assign of .META.
> ---------------------------------------------------------------------------------------------
>
> Key: HBASE-2235
> URL: https://issues.apache.org/jira/browse/HBASE-2235
> Project: Hadoop HBase
> Issue Type: Bug
> Reporter: stack
> Fix For: 0.20.4, 0.21.0
>
>
> Here is the short story:
> Scenario is a cluster of 3 servers. Server 1. crashed. It was carrying the
> .META. We split the logs. .META. is put on the head of the assignment
> queue. Server 2. happens to be in a state where it wants to report a split.
> The master fails the report because there is no .META. (It fails it ugly with
> a NPE). Server 3. checks in and falls into the assignment code
> (RegionManager#regionsAwaitingAssignment). In here we have this bit of code
> around line #412:
> {code}
> if (reassigningMetas && isMetaOrRoot && !isSingleServer) {
> return regionsToAssign; // dont assign anything to this server.
> }
> {code}
> Because we think this not a single server cluster -- we think there are two
> 'live' nodes -- we won't assign meta.
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