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sys.worker_id() ​

Return the logical ID of the worker node that runs this function.

sys.worker_id()

To return a meaningful result, always use this function in a query with a table reference, such as a reference to sys.const.

The following repeated queries return a different worker ID, depending on which worker runs the query in each case.

premdb=# select sys.worker_id() from sys.const;
 worker_id 
-----------
        9
(1 row)

premdb=# select sys.worker_id() from sys.const;
 worker_id 
-----------
        3
(1 row)

premdb=# select sys.worker_id() from sys.const;
 worker_id 
-----------
        8
(1 row)

The query counts the number of rows by the worker that processed the row (not the worker where the rows are stored).

premdb=# select sys.worker_id(), count(*) from newmatchstats group by 1 order by 1;
 worker_id | count  
-----------+--------
        0 |  68400
        1 |  34200
        4 |  41580
        5 |  75780
        6 |  34200
        7 |  34200
        8 | 102600
        9 | 102600
       10 | 144180
       12 |  68400
       13 |  68400
(11 rows)

Parent topic:System Functions