Altering Location Use

ALTER_LOCATION_USE lets you change the type of files that Vertica stores at a storage location. You typically use labels only for DATA storage locations, not TEMP.

This example shows how to alter the storage location on v_vmartdb_node0004 to store only data files:

=> SELECT ALTER_LOCATION_USE ('/thirdVerticaStorageLocation/' , 'v_vmartdb_node0004' , 'DATA');

Altering HDFS Storage Locations

When altering an HDFS storage location, you must make the change for each node in the Vertica cluster. You can make the change on all nodes at the same time by specifying a node value of '', as in the following example:

=> SELECT ALTER_LOCATION_USE('hdfs:///user/dbadmin/v_vmart',

USER Storage Location Restrictions

You cannot change a storage location from a USER usage type if you created the location that way, or to a USER type if you did not. You can change a USER storage location to specify DATA (storing TEMP files is not supported). However, doing so does not affect the primary objective of a USER storage location, to be accessible by non-dbadmin users with assigned privileges.

Effects of Altering Storage Location Use

Before altering a storage location use type, be aware that at least one location must remain for storing data and temp files on a node. You can store data and temp files in the same, or separate, storage locations.

Altering an existing storage location has the following effects:

Alter use from: To store only: Has this effect:

Temp and data files (or data only)

Temp files

Data content is eventually merged out through ATM, per its policies.You can also merge out data from the storage location manually using DO_TM_TASK.

The location stores only temp files from that point forward.

Temp and data files (or temp only)

Data files

Vertica continues to run all statements that use temp files (such as queries and loads).

Subsequent statements no longer use the changed storage location for temp files, and the location stores only data files from that point forward.