HBase Shell for MapR-DB

You can manage MapR-DB tables using HBase shell commands and additional HBase shell commands included in the MapR distribution of Hadoop.

The HBase shell command is used on binary tables only. To run this command, execute the following:

hbase shell
Note: Before running the shell, ensure that your user ID has both the readAce and writeAce permissions on the volume. For information about these permissions, see Whole Volume ACEs.

When you specify a table in HBase shell, use the following syntax:

  • For a table on the local cluster, start the path at the volume mount point. For example, for a table named test under a volume with a mount point at /volume1, specify the following path as the table name: “/volume1/test”
  • For a table on a remote cluster, you must also specify the cluster name in the path. For example, for a table named customer under volume1 in the sanfrancisco cluster, specify the following path as the table name: “/mapr/sanfrancisco/volume1/customer”
Note: You can access a table on a remote cluster when the remote cluster has an entry in the mapr-clusters.conf file on the node where the HBase shell is running.

The following table lists the supported HBase shell commands that you can use to manage MapR-DB tables:

Command Description
alter Performs the following actions on MapR-DB tables:
  • Adds a new table or column family
  • Modifies the following table-level attributes:
    • BULKLOAD - A Boolean value that specifies whether to perform a full bulk load of the table. The default is false. For more information, see Bulk Loading and MapR-DB Tables.
    • MAX_FILESIZE
    • AUTOSPLIT - A Boolean value that specifies whether to split the table into regions automatically as the table grows. The average size of each region is determined by the regionsizemb parameter. The default value is true. If you set the value to false, you can manually split tables into regions by using the maprcli table region split command.
  • Modifies the following attributes of a column family:
    • TTL
    • VERSIONS (max or min)
    • COMPRESSION
    • IN_MEMORY
Aside from the attributes listed above, no other attributes apply to MapR-DB tables. Unlike HBase, you do not need to disable a table before altering a table.
alter_async On MapR-DB tables, this has the same behavior as the alter command.
count Counts the number of rows in a specified table.
create Creates a table in the specified path.
delete Deletes a value in a specified table, row, and column. Optionally, you can also specify the timestamp associated with the value that you want to delete.
deleteall Delete all values in a row based on the table name and row. Optionally, you can also specify the timestamp associated with the values that you want to delete.
describe Describes a specified table.
disable Marks a specified table as disabled. This state is recorded only in the client process (HBase shell) memory and does not actually disable any operations on a MapR-DB table.
disable_all Marks tables as disabled if they have names matching the specified regular expression. This state is recorded only in the client process (HBase shell) memory and does not actually disable any operations on the MapR-DB tables.
drop Drops a specified table that is marked as disabled.
drop_all Drops all tables that are marked as disabled.
enable Marks a specified table as enabled. This state is recorded only in the client process (HBase shell) memory.
enable_all Marks tables as enabled if they have a table name that matches the specified regular expression. This state is recorded only in the client process (HBase shell) memory.
exists Returns boolean value true if the specified table exists.
exit Exits the HBase shell.
get Gets the contents of a row or cell.
get_counter Returns the value of a counter at a specified table, row, and column.
incr Increments a value at a specified table, row, and column.
is_disabled Returns a value that indicates if a specified table is disabled. You can perform operations on MapR-DB tables that are disabled.
is_enabled Returns a value that indicates if a specified table is enabled. You can perform operations on MapR-DB tables even if they are not enabled.
list When the HBase table namespace mapping points to a directory on the MapR-FS, the command lists all the MapR-DB tables in the specified MapR-FS directory. Otherwise, it lists all Apache HBase tables associated with the HBase service that is currently running. If the HBase table namespace mapping does not point to a directory on the MapR-FS and the HBase service is not running, it lists the tables in the home directory of the user that is running the HBase shell. For more information, see Mapping Table Namespace Between Apache HBase Tables and MapR-DB Tables.
list_perm Lists all permissions set by Access Control Expressions for a specified table. This HBase shell command only operates on MapR-DB tables. For more information, see list_perm.
put Puts a value at a specified table, row, and column. Optionally, you can also specify the timestamp for that value.
scan Scans a specified table. Optionally, you can also specify a dictionary of scanner specifications.
set_perm Sets permissions with Access Control Expressions on a specified table, column family, or column qualifier. This Hbase shell command only operates on MapR-DB tables. For more information, see set_perm.
show_filters Shows all the filters supported by the Hbase or MapR-DB tables. Provide the link to 4.1 supported filters doc
truncate Disables, drops, and recreates a specified table.
version Returns the HBase client version.
whoami Returns the current user.

MapR-DB does not support the following HBase shell commands:

  • add_peer
  • alter_status
  • assign
  • balance_switch
  • balancer
  • close_region
  • compact
  • disable_peer
  • enable_peer
  • flush
  • grant
  • hlog_roll
  • list_peer
  • major_compact
  • move
  • remove_peer
  • start_replication
  • stop_replication
  • status
  • split
  • revoke
  • unassign
  • user_permission
  • zk_dump

For more information about the HBase shell commands, see the Apache HBase documentation.