Grokbase Groups HBase dev July 2009
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[ https://issues.apache.org/jira/browse/HBASE-1684?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12741292#action_12741292 ]

Lars George commented on HBASE-1684:
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Stack, about your comments re: reducer/mapper needed. For the RestoreTable I am using both, the mapper reads from the backup files and then randomizes the rows using a random intermediate key. This is along what Ryan did with his pure randomizer MR class. That way all the RegionServers are hit equally.

For the BackupTable I am using an IdentityTableMapper and encode the data in the reducer to have it written out in the TextOutputFormat. After we discussed that a while ago with you and Jon it should also be possible to use only a Mapper and do the work there and set the Reducers to 0, which then hands out the Mapper records straight to the TextOutputFormat.

Lastly, implementing Tool seems deprecated. The new mapreduce WordCounter sample that comes with Hadoop 0.20 abandons it too. That is also why I changed RowCounter not to use it when I cleaned up the hbase.mapreduce package. The parsing of the generic options is done using the GenericParser directly inside the main(), and the remaining arguments used for the specific MR job. I have done the same in the attached two classes.
Backup (Export/Import) contrib tool for 0.20
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Key: HBASE-1684
URL: https://issues.apache.org/jira/browse/HBASE-1684
Project: Hadoop HBase
Issue Type: New Feature
Components: contrib
Affects Versions: 0.20.0
Reporter: Jonathan Gray
Assignee: Jonathan Gray
Fix For: 0.20.1

Attachments: BackupTable.java, HBASE-1684-v1.patch, RestoreTable.java


Add a new Result/KeyValue based Export MapReduce job to contrib for 0.20.
Make it in the hadoop 0.20 and hbase 0.20 MR API, and hbase 0.20 API (Result/Put).
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