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https://issues.apache.org/jira/browse/HADOOP-1528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12515061
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James Kennedy commented on HADOOP-1528:
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No problem. I'm just concerned that that HClient will evolve so much that this
patch will be out of date if it isn't already. It will take some work to
mirror recent improvements in HClient to the HConnection/HTable classes
although most methods are copied to them as is.
Since I'll be away for 3 weeks, i won't be able to update a new patch and/or
implement the above HClient facade for a while.
> HClient for multiple tables
> ---------------------------
>
> Key: HADOOP-1528
> URL: https://issues.apache.org/jira/browse/HADOOP-1528
> Project: Hadoop
> Issue Type: Task
> Components: contrib/hbase
> Affects Versions: 0.14.0
> Reporter: James Kennedy
> Assignee: Jim Kellerman
> Attachments: HConnection.patch
>
>
> I have an app that needs to access multiple HBase tables concurrently. The
> current HClient can only have one table open at a time even though it caches
> region servers of multiple tables as they are looked up.
> This means that my application layer must open multiple HClients, one per
> table, perhaps caching those HClients in a pool to reuse them (and their
> cached table data) as appropriate.
> or
> Shall I write an HClient patch that makes the HClient multi-table
> thread-safe?
> Jim's suggestion is to implement an HClient singleton (call it
> HClientManager?) that does the actual caching/resync of root/meta regions.
> Individual HClients will still be one table, one update row at a time but
> will rely on the singleton for the cached table info. We want HClients to be
> created and disposed as fast as possible with a minimum of meta lookups.
> Jim, what about non-root/meta regions, shouldn't they be cached and refreshed
> via the singleton also? It may still be possible that a region split/resync
> will occur during on HClient session so does the HClientManager need to be
> able to notify the corresponding HClients in that event?
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