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https://issues.apache.org/jira/browse/HADOOP-1528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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James Kennedy reassigned HADOOP-1528:
-------------------------------------

    Assignee: Jim Kellerman  (was: James Kennedy)

Assigning to Jim for comment.
Also I'll be on vacation for 3 weeks.

> 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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