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From "Lars Hofhansl (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-6505) Investigate shared RegionObserver state
Date Sat, 04 Aug 2012 06:11:02 GMT

    [ https://issues.apache.org/jira/browse/HBASE-6505?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13428569#comment-13428569
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Lars Hofhansl commented on HBASE-6505:
--------------------------------------

Thanks Andy.
I do have a new patch that uses a ReferenceMap (from the common collections library) with
hard keys and weak values (where the key would be the class name and the value be the class's
map).
As long as at least one RegionEnvironment exists to hold on to its reference of its map the
reference will not be removed from the ReferenceMap (and thus can be shared by other RegionEnvironment
for the same class), which is exactly what we want here (and much better than reference counting).
When it happens that all Envs for a specific class are blacklisted they will eventually be
garbage collected, which then allows the map entry to be collected.

Patch with test coming momentarily.

If you think that part is overkill and just makes it harder to understand - which might very
well be the case, I can easily revert back to the model I had before.

                
> Investigate shared RegionObserver state
> ---------------------------------------
>
>                 Key: HBASE-6505
>                 URL: https://issues.apache.org/jira/browse/HBASE-6505
>             Project: HBase
>          Issue Type: Sub-task
>            Reporter: Lars Hofhansl
>            Assignee: Lars Hofhansl
>             Fix For: 0.96.0, 0.94.2
>
>         Attachments: 6505-v2.txt, 6505.txt
>
>


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