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https://issues.apache.org/jira/browse/HBASE-3777?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13026821#comment-13026821
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M. C. Srivas commented on HBASE-3777:
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It seems error-prone to compare conf's to identify clusters.
The mapping should really be "cluster uuid" (if such a thing exists) to
connection. Perhaps there's a hmaster md5 that can be used in lieu of
cluster-uuid sitting in ZK that can be probed?
Then, an alternative other way is to go ahead and make the extra connection and
use it to determine which cluster the client is going against. If it's a
previously-seen cluster, close this newly-created connection, and use the
stashed one. Else this is a new cluster and create a new mapping entry.
> Redefine Identity Of HBase Configuration
> ----------------------------------------
>
> Key: HBASE-3777
> URL: https://issues.apache.org/jira/browse/HBASE-3777
> Project: HBase
> Issue Type: Improvement
> Components: client, ipc
> Affects Versions: 0.90.2
> Reporter: Karthick Sankarachary
> Assignee: Karthick Sankarachary
> Priority: Minor
> Fix For: 0.92.0
>
> Attachments: 3777-TOF.patch, HBASE-3777-V2.patch,
> HBASE-3777-V3.patch, HBASE-3777-V4.patch, HBASE-3777-V6.patch,
> HBASE-3777.patch
>
>
> Judging from the javadoc in {{HConnectionManager}}, sharing connections
> across multiple clients going to the same cluster is supposedly a good thing.
> However, the fact that there is a one-to-one mapping between a configuration
> and connection instance, kind of works against that goal. Specifically, when
> you create {{HTable}} instances using a given {{Configuration}} instance and
> a copy thereof, we end up with two distinct {{HConnection}} instances under
> the covers. Is this really expected behavior, especially given that the
> configuration instance gets cloned a lot?
> Here, I'd like to play devil's advocate and propose that we "deep-compare"
> {{HBaseConfiguration}} instances, so that multiple {{HBaseConfiguration}}
> instances that have the same properties map to the same {{HConnection}}
> instance. In case one is "concerned that a single {{HConnection}} is
> insufficient for sharing amongst clients", to quote the javadoc, then one
> should be able to mark a given {{HBaseConfiguration}} instance as being
> "uniquely identifiable".
> Note that "sharing connections makes clean up of {{HConnection}} instances a
> little awkward", unless of course, you apply the change described in
> HBASE-3766.
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