sys.dm_exec_external_work (Transact-SQL)
Applies to: 
SQL Server 2016 (13.x) and later versions
Returns information about the workload per worker, on each compute node.
Query sys.dm_exec_external_work to identify the work spun up to communicate with the external data source (for example, Hadoop or MongoDB).
| Column Name | Data Type | Description | Range |
|---|---|---|---|
| execution_id | nvarchar(32) |
Unique identifier for associated PolyBase query. | See request_ID in sys.dm_exec_requests (Transact-SQL). |
| step_index | int |
The request this worker is performing. | See step_index in sys.dm_exec_requests (Transact-SQL). |
| dms_step_index | int |
Step in the DMS plan that this worker is executing. | See sys.dm_exec_dms_workers (Transact-SQL). |
| compute_node_id | int |
The node the worker is running on. | See sys.dm_exec_compute_nodes (Transact-SQL). |
| type | nvarchar(60) |
The type of external work. | 'File Split' (for Hadoop and Azure storage) 'ODBC Data Split' (for other external data sources) |
| work_id | int |
ID of the actual split. | Greater than or equal to 0. |
| input_name | nvarchar(4000) |
Name of the input to be read | File name (with path) when using Hadoop or Azure storage. For other external data sources, it is the concatenation of the external data source location and the external table location: scheme://DataSourceHostname[:port]/[DatabaseName.][SchemaName.]TableName |
| read_location | bigint |
Offset of read location. | 0 to the number of bytes in the file minus 1.NULL for non-Hadoop or non-Azure storage. |
| read_command | nvarchar(4000) |
The query that is sent to the external data source. Introduced in SQL Server 2019 (15.x). | Text representing the query. For Hadoop and Azure storage returns NULL. |
| bytes_processed | bigint |
Total bytes allocated for processing data by this worker. This value may not necessarily represent the total data being returned by the query | Greater than or equal to 0. |
| length | bigint |
Length of the split or, HDFS block for Hadoop | User-definable. The default is 64M |
| status | nvarchar(32) |
Status of the worker | Pending, Processing, Done, Failed, Aborted |
| start_time | datetime |
Beginning of the work | |
| end_time | datetime |
End of the work | |
| total_elapsed_time | int |
Total time in milliseconds | |
| compute_pool_id | int |
Unique identifier for the pool where the worker is running. Only applies to SQL Server Big Data Cluster. See sys.dm_exec_compute_pools (Transact-SQL). | Returns 0 for SQL Server on Windows and Linux. |
Remarks
Starting with SQL Server 2019 (15.x), you can use sys.dm_exec_external_work to view the remote query passed to an external data source in PolyBase pushdown computation. For more information, see How to tell if external pushdown occurred.
See also
PolyBase troubleshooting with dynamic management views
Dynamic Management Views and Functions (Transact-SQL)
Database Related Dynamic Management Views (Transact-SQL)