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From "marco polo (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (ACCUMULO-3509) Scanner lock cause Tablet lock, hence preventing idle scans from being swept, hence blocking SimpleTimer thread
Date Thu, 22 Jan 2015 18:16:35 GMT

     [ https://issues.apache.org/jira/browse/ACCUMULO-3509?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

marco polo updated ACCUMULO-3509:
---------------------------------
    Summary: Scanner lock cause Tablet lock, hence preventing idle scans from being swept,
hence blocking SimpleTimer thread   (was: Scanner lock will prevent idle scans to be locked,
hence blocking SimpleTimer thread)

> Scanner lock cause Tablet lock, hence preventing idle scans from being swept, hence blocking
SimpleTimer thread 
> ----------------------------------------------------------------------------------------------------------------
>
>                 Key: ACCUMULO-3509
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3509
>             Project: Accumulo
>          Issue Type: Bug
>          Components: tserver
>    Affects Versions: 1.6.0
>            Reporter: marco polo
>            Assignee: marco polo
>             Fix For: 1.7.0, 1.6.3
>
>
> Synchronization with Tablet$Scanner via a read() will block close() being called via
the sweep method in TabletServer. As a result, the SimpleTimer thread does not continue, and
idle threads grow until the scan completes. 
> My patch, which is forthcoming, converts synchronized methods to use a fair lock. If
the lock is held by a read call, the close call will attempt to obtain it, time out, and return
indicating a close was not successful. The sweep will continue, and the SimpleTimer thread
will respawn later, attempting closure on those Tablets at a later time. 



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