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From "John Omernik (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DRILL-4286) Have an ability to put server in quiescent mode of operation
Date Fri, 10 Jun 2016 16:10:20 GMT

    [ https://issues.apache.org/jira/browse/DRILL-4286?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15324707#comment-15324707
] 

John Omernik commented on DRILL-4286:
-------------------------------------

What if the Drill bit only rejected work when it was in a "DRAINED" state, however, for those
queries that were planned to include a bit, then the bit state was changed to draining, that
work could get added to the queue.  This would eliminate the race condition, and would only
rely on the foreman checking the znode at planning time.  This could extend the draining state
a bit, but that time is less important than say having to recheck node state, or getting a
reject from a drillbit causing the foreman to replan the query.  Basically, only those queries
that were planned AFTER the drillbit state was changed to draining or drained would not include
the drillbit.  



> Have an ability to put server in quiescent mode of operation
> ------------------------------------------------------------
>
>                 Key: DRILL-4286
>                 URL: https://issues.apache.org/jira/browse/DRILL-4286
>             Project: Apache Drill
>          Issue Type: New Feature
>          Components: Execution - Flow
>            Reporter: Victoria Markman
>
> I think drill will benefit from mode of operation that is called "quiescent" in some
databases. 
> From IBM Informix server documentation:
> {code}
> Change gracefully from online to quiescent mode
> Take the database server gracefully from online mode to quiescent mode to restrict access
to the database server without interrupting current processing. After you perform this task,
the database server sets a flag that prevents new sessions from gaining access to the database
server. The current sessions are allowed to finish processing. After you initiate the mode
change, it cannot be canceled. During the mode change from online to quiescent, the database
server is considered to be in Shutdown mode.
> {code}
> This is different from shutdown, when processes are terminated. 



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