Viewing Table Regions

MapR Database tables are split into regions on an ongoing basis. Administrators and developers do not need to manage these regions or restructure data on disk when data is added and deleted. These operations happen automatically. You can view region information for tables to get a sense of the size and location of table data on the MapR cluster.

You can use either the MCS or the CLI to list the regions in which a table's data is located.

Displaying the Regions Using the MapR Control System

To display the regions of a table:

  1. Go to the table information page.
  2. Do one of the following:
    • Click Regions to view the list of regions for the table.
    • Click the name of the index in the Indexes tab to view the regions for the index.
    For each region, the Regions pane displays the following:
    Column Name Column Description
    Start Key Value of the start key for this region. For the first region in a table, this value is exclusive. For all other regions, it is inclusive.
    End Key Value of the end key for this region. This value is always exclusive.
    Physical Size The physical size of the region with data compression (excluding replication).
    Logical Size The logical size of the region without data compression (excluding replication).
    No of Rows Number of rows in the region.
    Primary Node The host name and port of the primary node for this region.
    Secondary Node The host names and ports of the secondary nodes where this region is replicated.
    Last HB The time since last heartbeat from the region's primary node.
    Region Identifier The region's FID.

Displaying Region Information Using the CLI or the REST API

The basic command to retrieve the list of regions that make up the table is:

maprcli table region list -path <path>
  • For a path 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: /volume1/test
  • For a path 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:/mapr/sanfrancisco/volume1/customer
The json parameter displays the output as a JSON document.
To run this command, your user ID must have the following permissions:
  • readAce on the volume
  • lookupdir on directories in the path

See table region list.