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Posted to issues@hbase.apache.org by "jiraposter@reviews.apache.org (JIRA)" <ji...@apache.org> on 2011/09/22 02:39:27 UTC

[jira] [Commented] (HBASE-4455) Rolling restart RSs scenario, -ROOT-, .META. regions are lost in AssignmentManager

    [ https://issues.apache.org/jira/browse/HBASE-4455?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13112264#comment-13112264 ] 

jiraposter@reviews.apache.org commented on HBASE-4455:
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Review request for hbase.


Summary
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1. Add more logging.
2. Clean up CatalogTracker. waitForMeta waits for "timeout" value. When waitForMetaServerConnectionDefault is called by MetaNodeTracker, the timeout value is large. So it doesn't retry in case .ROOT. is updated; add the proper implementation for CatalogTracker.verifyMetaRegionLocation
4. Check for the latest -ROOT- and .META. region location during the handling of server shutdown.
5. Right after assigning the -ROOT- or .META. in ServerShutdownHandler, don't block and wait for .META. availability. Resubmit another ServerShutdownHandler for regular regions.


This addresses bug HBASE-4455.
    https://issues.apache.org/jira/browse/HBASE-4455


Diffs
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  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/handler/CloseRegionHandler.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/handler/OpenRegionHandler.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/MetaNodeTracker.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/handler/OpenedRegionHandler.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/handler/ServerShutdownHandler.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/handler/MetaServerShutdownHandler.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/ServerManager.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/catalog/CatalogTracker.java 1172205 
  http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperNodeTracker.java 1172205 

Diff: https://reviews.apache.org/r/2007/diff


Testing
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Keep Master up all the time, do rolling restart of RSs like this - stop RS1, wait for 2 seconds, stop RS2, start RS1, wait for 2 seconds, stop RS3, start RS2, wait for 2 seconds, etc. The program can run for couple hours until it stops. -ROOT- and .META. are available during that time.


Thanks,

Ming



> Rolling restart RSs scenario, -ROOT-, .META. regions are lost in AssignmentManager
> ----------------------------------------------------------------------------------
>
>                 Key: HBASE-4455
>                 URL: https://issues.apache.org/jira/browse/HBASE-4455
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Ming Ma
>            Assignee: Ming Ma
>
> Keep Master up all the time, do rolling restart of RSs like this - stop RS1, wait for 2 seconds, stop RS2, start RS1, wait for 2 seconds, stop RS3, start RS2, wait for 2 seconds, etc. After a while, you will find the -ROOT-, .META. regions aren't in "regions in transtion" from AssignmentManager point of view, but they aren't assigned to any regions. Here are the issues.
> 1. .-ROOT- or .META. location is stale when MetaServerShutdownHandler is invoked to check if it contains -ROOT- region. That is due to long delay from ZK notification and async nature of the system. Here is an example, even though new root region server sea-lab-1,60020,1316380133656 is set at T2, at T3 the shutdown process for sea-lab-1,60020,1316380133656, the root location still points to old server sea-lab-3,60020,1316380037898.
> T1: 2011-09-18 14:08:52,470 DEBUG org.apache.hadoop.hbase.zookeeper.ZKUtil: master:6
> 0000-0x1327e43175e0000 Retrieved 29 byte(s) of data from znode /hbase/root-regio
> n-server and set watcher; sea-lab-3,60020,1316380037898
> T2: 2011-09-18 14:08:57,173 INFO org.apache.hadoop.hbase.catalog.RootLocationEditor: Setting ROOT region location in ZooKeeper as sea-lab-1,60020,1316380133656
> T3: 2011-09-18 14:10:26,393 DEBUG org.apache.hadoop.hbase.master.ServerManager: Adde
> d=sea-lab-1,60020,1316380133656 to dead servers, submitted shutdown handler to be executed, root=false, meta=true, current Root Location: sea-lab-3,60020,1316380037898
> T4: 2011-09-18 14:12:37,314 DEBUG org.apache.hadoop.hbase.zookeeper.ZKUtil: master:6
> 0000-0x1327e43175e0000 Retrieved 29 byte(s) of data from znode /hbase/root-region-server and set watcher; sea-lab-1,60020,1316380133656
> 2. The MetaServerShutdownHandler worker thread that waits for -ROOT- or .META. availability could be blocked. If meanwhile, the new server that -ROOT- or .META. is being assigned restarted, another instance of MetaServerShutdownHandler is queued. Eventually, all MetaServerShutdownHandler worker threads are filled up. It looks like HBASE-4245.

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