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Posted to issues@hbase.apache.org by "Eugene Koontz (JIRA)" <ji...@apache.org> on 2010/05/15 00:42:49 UTC
[jira] Updated: (HBASE-2486) Add simple "anti-entropy" for region
assignment
[ https://issues.apache.org/jira/browse/HBASE-2486?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Eugene Koontz updated HBASE-2486:
---------------------------------
Status: Patch Available (was: Open)
Release Note:
Adds new property "hbase.master.sanitychecking" which determines how master should handle situations where the master believes a region is hosted by a certain regionserver, but that regionserver indicates by throwing a 'No Such Region' exception, that it does not serve that region:
lax - mark region as unassigned and continue
paranoid - shut down master
Note that this patch is against 0.20.3; I can create another patch against 0.20.4 and/or other tags if desired by reviewer.
> Add simple "anti-entropy" for region assignment
> -----------------------------------------------
>
> Key: HBASE-2486
> URL: https://issues.apache.org/jira/browse/HBASE-2486
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: master, regionserver
> Affects Versions: 0.20.5
> Reporter: Todd Lipcon
> Assignee: Eugene Koontz
> Fix For: 0.21.0
>
>
> We've seen a number of bugs where a region server thinks it should not be serving a region, but the master and META think it should be. I'd like to propose a very simple way of fixing this issue:
> 1) whenever a regionserver throws a NotServingRegionException, it also marks that region id in an RS-wide Set
> 2) when a region sends a heartbeat, include a message for each of these regions, MSG_REPORT_NSRE or somesuch, and then clear the set
> 3) when the master receives MSG_REPORT_NSRE, it does the following checks:
> a) if the region is assigned elsewhere according to META, the NSRE was due to a stale client, ignore
> b) if the region is in transition, ignore
> c) otherwise, we have an inconsistency, and we should take some steps to resolve (eg mark the region unassigned, or exit the master if we are in "paranoid mode")
> Whatever we do, we need to make sure that this is loudly logged, and causes unit tests to fail, when it's detected. This should *not* happen, but when it does, it would be good to recover without addtable.rb, etc.
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