How to list the regions in an HBase table through the shell?

Question

I would like to get the same information about the regions of a table that appear in the web UI (i.e. region name, region server, start/end key, locality), but through the hbase shell.

(The UI is flaky/slow, and furthermore I want to process this information as part of a script.)

After much googling, I can't find out how, and this surprises me immensely. version is 1.0.0.-cdh5.4.0

Answer 1

To get the region info about the table, you need to scan hbase:meta table.

scan 'hbase:meta',{FILTER=>"PrefixFilter('table_name')"}

This command will give details of all the regions. Row key will have region name and there will be four column qualifiers. You may need following two column qualifiers:

info:regioninfo - This qualifier contains STARTKEY and ENDKEY.

info:server - This qualifier contains region server details

Answer 2

Use the "official" list_regions shell command to list out all the regions. Note that this tool is available only starting from HBase versions 1.4 and above.

Some examples are 
        Examples:
        hbase> list_regions 'table_name'
        hbase> list_regions 'table_name', 'server_name'
        hbase> list_regions 'table_name', {SERVER_NAME => 'server_name', LOCALITY_THRESHOLD => 0.8}
        hbase> list_regions 'table_name', {SERVER_NAME => 'server_name', LOCALITY_THRESHOLD => 0.8}, ['SERVER_NAME']
        hbase> list_regions 'table_name', {}, ['SERVER_NAME', 'start_key']
        hbase> list_regions 'table_name', '', ['SERVER_NAME', 'start_key']

Details on its implementation are at: https://issues.apache.org/jira/browse/HBASE-14925

Answer 3

scan 'hbase:meta', {FILTER=>"PrefixFilter('tableName')", COLUMNS=>['info:regioninfo']}