DESCRIBE EXTERNAL VOLUME¶

Describes the properties of an external volume.

DESCRIBE can be abbreviated to DESC.

See also:: ALTER EXTERNAL VOLUME , CREATE EXTERNAL VOLUME , DROP EXTERNAL VOLUME , SHOW EXTERNAL VOLUMES

Syntax¶

DESC[RIBE] EXTERNAL VOLUME <name>

Parameters¶

name: Specifies the identifier for the external volume to describe. If the identifier contains spaces or special characters, the entire string must be enclosed in double quotes (for example, "My object"). Identifiers enclosed in double quotes are also case-sensitive.

Output¶

The output of the command includes the following columns, which describe the properties and metadata of the object:

Column	Description
`parent_property`	The parent property. This column includes the `STORAGE_LOCATIONS` property, which holds a set of named cloud storage locations.
`property`	The name of the property. This column can include the properties listed in the following table.
`property_type`	The property type.
`property_value`	The value assigned to the property.
`property_default`	The default property value.

The property column can include the following properties of an external volume object:

Property	Description
`comment`	The comment set for the external volume, if any.
`allow_writes`	Specifies whether write operations are allowed for the external volume.
`storage_location_n`	Details for a cloud storage location associated with the external volume, where `n` is a unique number that distinguishes the location from others in the `STORAGE_LOCATIONS` list; for example, `storage_location_1`. For more information about storage location properties, see CREATE EXTERNAL VOLUME.
`active`	The name of the active storage location for the external volume.

Access control requirements¶

A role used to execute this operation must have the following privileges at a minimum:

Privilege	Object	Notes
USAGE	External volume

For instructions on creating a custom role with a specified set of privileges, see Creating custom roles.

For general information about roles and privilege grants for performing SQL actions on securable objects, see Overview of Access Control.

Usage notes¶

To post-process the output of this command, you can use the pipe operator (->>) or the RESULT_SCAN function. Both constructs treat the output as a result set that you can query.

For example, you can use the pipe operator or RESULT_SCAN function to select specific columns from the SHOW command output or filter the rows.

When you refer to the output columns, use double-quoted identifiers for the column names. For example, to select the output column type, specify SELECT "type".

You must use double-quoted identifiers because the output column names for SHOW commands are in lowercase. The double quotes ensure that the column names in the SELECT list or WHERE clause match the column names in the SHOW command output that was scanned.

Examples¶

Describe an external volume:

DESC EXTERNAL VOLUME my_external_volume;

The following shows the output of DESCRIBE EXTERNAL VOLUME for an external volume with one storage location. The property value for STORAGE_LOCATION_1 is abbreviated for display purposes.

+-------------------+--------------------+---------------+-------------------------------------------------------------------------------------------+------------------+
| parent_property   | property           | property_type | property_value                                                                            | property_default |
|-------------------+--------------------+---------------+-------------------------------------------------------------------------------------------+------------------|
|                   | ALLOW_WRITES       | Boolean       | true                                                                                      | true             |
| STORAGE_LOCATIONS | STORAGE_LOCATION_1 | String        | {"NAME":"my_storage_us_west","STORAGE_PROVIDER":"S3","STORAGE_BASE_URL":"s3china://...", ...}  |                  |
| STORAGE_LOCATIONS | ACTIVE             | String        | my_storage_us_west                                                                        |                  |
+-------------------+--------------------+---------------+-------------------------------------------------------------------------------------------+------------------+