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https://issues.apache.org/jira/browse/HBASE-2426?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12854974#action_12854974
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George P. Stathis commented on HBASE-2426:
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This patch builds right on top of HBASE-2286. So the latter is required (it's
already committed so it should not be a problem as long as folks SVN up the
latest from the branch).
> [Transactional Contrib] Introduce quick scanning row-based secondary indexes
> ----------------------------------------------------------------------------
>
> Key: HBASE-2426
> URL: https://issues.apache.org/jira/browse/HBASE-2426
> Project: Hadoop HBase
> Issue Type: New Feature
> Components: contrib
> Reporter: George P. Stathis
> Priority: Minor
> Fix For: 0.20.5, 0.21.0
>
> Attachments: hbase-2426-0.20-branch.patch
>
>
> RowBasedIndexSpecification is a specialized IndexSpecification class for
> creating row-based secondary index tables. Base table rows with the same
> indexed column value have their row keys stored as column qualifiers on the
> same secondary index table row. The key for that row is the indexed column
> value from the base table. This allows to avoid expensive secondary index
> table scans and provides faster access for applications such as foreign key
> indexing or queries such as "find all table A rows whose familyA:columnB
> value is X". RowBasedIndexSpecification indices can be scanned using the API
> on RowBasedIndexedTable. The metadata for RowBasedIndexSpecification differ
> from IndexSpecification in that:
> - Only a single base table column can be indexed per
> RowBasedIndexSpecification. No additional columns are put in the index table.
> and
> - RowBasedIndexKeyGenerator, which constructs the index-row-key from the
> indexed column value in the original column, is always used.
> For a simple RowBasedIndexSpecification example, look at the
> TestRowBasedIndexedTable unit test in
> org.apache.hadoop.hbase.client.tableIndexed.
> To enable RowBasedIndexSpecification indexing, modify hbase-site.xml to turn
> on the
> IndexedRegionServer. This is done by setting
> - hbase.regionserver.class to
> org.apache.hadoop.hbase.ipc.IndexedRegionInterface and
> - hbase.regionserver.impl to
> org.apache.hadoop.hbase.regionserver.tableindexed.RowBasedIndexedRegionServer
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