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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (TEPHRA-244) Invalid tx pruning does not handle deletion of tables well
Date Mon, 11 Sep 2017 04:43:02 GMT

    [ https://issues.apache.org/jira/browse/TEPHRA-244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16160669#comment-16160669
] 

ASF GitHub Bot commented on TEPHRA-244:
---------------------------------------

GitHub user poornachandra opened a pull request:

    https://github.com/apache/incubator-tephra/pull/55

    TEPHRA-244 Remove regions of deleted tables when computing prune upper bound

    JIRA - https://issues.apache.org/jira/browse/TEPHRA-244
    
    This PR just removes regions of deleted tables when computing prune upper bound. This
ensures that transient tables do not block pruning. However, if a transient table is created/deleted
again with the same name and never gets a chance to be compacted, then it has a potential
to block pruning.
    


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/poornachandra/incubator-tephra feature/prune-transient-tables

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/incubator-tephra/pull/55.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #55
    
----
commit ddfed1bf9f764cf2a29d900ed55f283b45861d02
Author: poorna <poorna@cask.co>
Date:   2017-09-11T04:38:08Z

    TEPHRA-244 Remove regions of deleted tables when computing prune upper bound

----


> Invalid tx pruning does not handle deletion of tables well
> ----------------------------------------------------------
>
>                 Key: TEPHRA-244
>                 URL: https://issues.apache.org/jira/browse/TEPHRA-244
>             Project: Tephra
>          Issue Type: Bug
>          Components: core, manager
>    Affects Versions: 0.12.0-incubating
>            Reporter: Andreas Neumann
>            Assignee: Poorna Chandra
>             Fix For: 0.13.0-incubating
>
>
> Suppose an application regularly creates and deletes tables (for example, temporary tables).
In such a scenario, there will always be such a temporary table when pruning runs, and its
regions will be recorded for that time. However, the region will be deleted before it ever
compacts or flushes, and it will never record prune information. Because all prune times have
such regions, there will never be a set of transactional regions that all have prune info,
and pruning will never happen. 
> The fix is to exclude deleted tables from the list of regions at each time. This is all
regions of deleted tables (tables that do not exist any more), not deleted regions: a region
may disappear due to a split and its data will be in new regions. 



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