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https://issues.apache.org/jira/browse/HBASE-5155?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13182653#comment-13182653
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Zhihong Yu commented on HBASE-5155:
-----------------------------------

Then we need to detect whether the table being deleted/disabled has region on 
the underlying server.
                
> ServerShutDownHandler And Disable/Delete should not happen parallely leading 
> to recreation of regions that were deleted
> -----------------------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-5155
>                 URL: https://issues.apache.org/jira/browse/HBASE-5155
>             Project: HBase
>          Issue Type: Bug
>          Components: master
>    Affects Versions: 0.90.4
>            Reporter: ramkrishna.s.vasudevan
>            Priority: Blocker
>
> ServerShutDownHandler and disable/delete table handler races.  This is not an 
> issue due to TM.
> -> A regionserver goes down.  In our cluster the regionserver holds lot of 
> regions.
> -> A region R1 has two daughters D1 and D2.
> -> The ServerShutdownHandler gets called and scans the META and gets all the 
> user regions
> -> Parallely a table is disabled. (No problem in this step).
> -> Delete table is done.
> -> The tables and its regions are deleted including R1, D1 and D2.. (So META 
> is cleaned)
> -> Now ServerShutdownhandler starts to processTheDeadRegion
> {code}
>  if (hri.isOffline() && hri.isSplit()) {
>       LOG.debug("Offlined and split region " + hri.getRegionNameAsString() +
>         "; checking daughter presence");
>       fixupDaughters(result, assignmentManager, catalogTracker);
> {code}
> As part of fixUpDaughters as the daughers D1 and D2 is missing for R1 
> {code}
>     if (isDaughterMissing(catalogTracker, daughter)) {
>       LOG.info("Fixup; missing daughter " + daughter.getRegionNameAsString());
>       MetaEditor.addDaughter(catalogTracker, daughter, null);
>       // TODO: Log WARN if the regiondir does not exist in the fs.  If its not
>       // there then something wonky about the split -- things will keep going
>       // but could be missing references to parent region.
>       // And assign it.
>       assignmentManager.assign(daughter, true);
> {code}
> we call assign of the daughers.  
> Now after this we again start with the below code.
> {code}
>         if (processDeadRegion(e.getKey(), e.getValue(),
>             this.services.getAssignmentManager(),
>             this.server.getCatalogTracker())) {
>           this.services.getAssignmentManager().assign(e.getKey(), true);
> {code}
> Now when the SSH scanned the META it had R1, D1 and D2.
> So as part of the above code D1 and D2 which where assigned by fixUpDaughters
> is again assigned by 
> {code}
> this.services.getAssignmentManager().assign(e.getKey(), true);
> {code}
> Thus leading to a zookeeper issue due to bad version and killing the master.
> The important part here is the regions that were deleted are recreated which 
> i think is more critical.

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