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https://issues.apache.org/jira/browse/HBASE-10349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13874924#comment-13874924
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Jimmy Xiang commented on HBASE-10349:
-------------------------------------
The test is ok locally. Let me take a look and post a new patch.
[~mbertozzi], it is a racing between table deletion and balancer. The balancer
operates on a "copy" of the region assignments. When the balancer tries to
balance a region, the region has been deleted (including the meta entry), and
the table is removed (including the znode). In assigning the deleted region,
the region server puts the region back in the meta again with just the server
info. That's why the region info in the meta row is missing.
> Table became unusable when master balanced its region after table was dropped
> -----------------------------------------------------------------------------
>
> Key: HBASE-10349
> URL: https://issues.apache.org/jira/browse/HBASE-10349
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.98.0
> Reporter: Ted Yu
> Assignee: Jimmy Xiang
> Fix For: 0.98.0, 0.99.0
>
> Attachments:
> 10349-hadoop-hdfs-namenode-hor11n14.gq1.ygridcore.net.zip, 10349-output.log,
> 10349-v1.txt, 10349-v2.txt, HBASE-10349-meta-test-and-debug.patch,
> hbase-10349.patch, hbase-hbase-master-hor15n05.gq1.ygridcore.net.log.tar.gz
>
>
> 0.98 was used.
> This was sequence of events:
> create 'tablethree_mod'
> snapshot 'tablethree_mod', 'snapshot_tablethree_mod'
> disable 'tablethree_mod'
> 2014-01-15 09:34:51,749 restore_snapshot 'snapshot_tablethree_mod'
> 2014-01-15 09:35:07,210 enable 'tablethree_mod'
> 2014-01-15 09:35:46,134 delete_snapshot 'snapshot_tablethree_mod'
> 2014-01-15 09:41:42,210 disable 'tablethree_mod'
> 2014-01-15 09:41:43,610 drop 'tablethree_mod'
> create 'tablethree_mod'
> For the last table creation request:
> {code}
> 2014-01-15 10:03:52,999|beaver.component.hbase|INFO| 'create 'tablethree_mod',
> {NAME => 'f1', VERSIONS => 3}
> ,
> {NAME => 'f2', VERSIONS => 3}
> ,
> {NAME => 'f3', VERSIONS => 3}
> '
> 2014-01-15 10:03:52,999|beaver.component.hbase|INFO| 'exists 'tablethree_mod''
> 2014-01-15 10:03:52,999|beaver.component.hbase|INFO| 'put 'tablethree_mod',
> '0', 'f1:q1', 'value-0', 10'
> 2014-01-15 10:03:52,999|beaver.component.hbase|INFO| 'put 'tablethree_mod',
> '1', 'f1:q1', 'value-1', 20'
> 2014-01-15 10:03:53,000|beaver.component.hbase|INFO| 'put 'tablethree_mod',
> '2', 'f2:q2', 'value-2', 30'
> 2014-01-15 10:03:53,000|beaver.component.hbase|INFO| 'put 'tablethree_mod',
> '3', 'f3:q3', 'value-3', 40'
> 2014-01-15 10:03:53,000|beaver.component.hbase|INFO| 'put 'tablethree_mod',
> '4', 'f3:q3', 'value-4', 50'
> 2014-01-15 10:03:53,000|beaver.component.hbase|INFO|Done writing commands to
> file. Will execute them now.
> 2014-01-15 10:03:53,000|beaver.machine|INFO|RUNNING: /usr/lib/hbase/bin/hbase
> shell /grid/0/tmp/hwqe/artifacts/tmp-471142
> 2014-01-15 10:03:55,878|beaver.machine|INFO|2014-01-15 10:03:55,878 INFO
> [main] Configuration.deprecation: hadoop.native.lib is deprecated. Instead,
> use io.native.lib.available
> 2014-01-15 10:03:57,283|beaver.machine|INFO|2014-01-15 10:03:57,283 WARN
> [main] conf.Configuration: hbase-site.xml:an attempt to override final
> parameter: dfs.support.append; Ignoring.
> 2014-01-15 10:03:57,669|beaver.machine|INFO|2014-01-15 10:03:57,669 WARN
> [main] conf.Configuration: hbase-site.xml:an attempt to override final
> parameter: dfs.support.append; Ignoring.
> 2014-01-15 10:03:57,720|beaver.machine|INFO|2014-01-15 10:03:57,720 WARN
> [main] conf.Configuration: hbase-site.xml:an attempt to override final
> parameter: dfs.support.append; Ignoring.
> 2014-01-15 10:03:57,997|beaver.machine|INFO|
> 2014-01-15 10:03:57,997|beaver.machine|INFO|ERROR: Table already exists:
> tablethree_mod!
> 2014-01-15 10:03:57,997|beaver.machine|INFO|
> {code}
> This was an intermittent issue after using Snapshots, a table is not properly
> dropped / and not able to properly re-create with the same name. And a
> HRegion is empty or null Error occurs. (When you try to drop the table it
> says it does not exist, and when you try to create the table it says that it
> does already exist).
> {code}
> 2014-01-15 10:04:02,462|beaver.machine|INFO|ERROR: HRegionInfo was null or
> empty in hbase:meta, row=keyvalues=
> {tablethree_mod,,1389778226606.afc82d1ceabbaca36a504b83b65fc0c9./info:seqnumDuringOpen/1389778905355/Put/vlen=8/mvcc=0,
>
> tablethree_mod,,1389778226606.afc82d1ceabbaca36a504b83b65fc0c9./info:server/1389778905355/Put/vlen=32/mvcc=0,
>
> tablethree_mod,,1389778226606.afc82d1ceabbaca36a504b83b65fc0c9./info:serverstartcode/1389778905355/Put/vlen=8/mvcc=0}
>
> {code}
> Thanks to Huned who discovered this issue.
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