[HBASE-11657] Put HTable region methods in an interface

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.99.0
• Fix Version/s: 0.99.0
• Hadoop Flags: Reviewed
• Release Note: Add a RegionLocator Interface. Encapsulates 'region' operations. Implemented by HTable and you can get one from an HConnection.
• Assignee: Carter
• Reporter: Carter
• Created: 04/Aug/14 14:38
• Updated: 06/Apr/18 17:51
• Resolved: 19/Aug/14 23:19

Description

Most of the HTable methods are now abstracted by HTableInterface, with the notable exception of the following methods that pertain to region metadata:

HRegionLocation getRegionLocation(final String row)
HRegionLocation getRegionLocation(final byte [] row)
HRegionLocation getRegionLocation(final byte [] row, boolean reload)
byte [][] getStartKeys()
byte[][] getEndKeys()
Pair<byte[][],byte[][]> getStartEndKeys()
void clearRegionCache()

and a default scope method which maybe should be bundled with the others:

List<RegionLocations> listRegionLocations()

Since the consensus seems to be that these would muddy HTableInterface with non-core functionality, where should it go? MapReduce looks up the region boundaries, so it needs to be exposed somewhere.

Let me throw out a straw man to start the conversation. I propose:

org.apache.hadoop.hbase.client.HRegionInterface

Have HTable implement this interface. Also add these methods to HConnection:

HRegionInterface getTableRegion(TableName tableName)
HRegionInterface getTableRegion(TableName tableName, ExecutorService pool)

stack, ndimiduk, enis, thoughts?