MapR-DB Format

The MapR-DB format is not included in the Apache Drill release. Drill includes a maprdb format for MapR-DB that is defined within the default dfs storage plugin configuration when you install Drill from the mapr-drill package on a MapR node. The maprdb format improves the estimated number of rows that Drill uses to plan a query. It also enables you to query tables like you would query files in a file system because MapR-DB and MapR-FS share the same namespace.

You can query tables stored across multiple directories. You do not need to create a table mapping to a directory before you query a table in the directory. You can select from any table in any directory the same way you would select from files in MapR-FS, using the same syntax.

Instead of including the name of a file, you include the table name in the query. The userid running the query must have read permission to access the MapR table.

Example

   SELECT * FROM mfs.`/users/max/mytable`;  

The following image shows a portion of the dfs configuration with the maprdb format: