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New in v1.1: The CANCEL QUERY statement cancels a running SQL query.
Considerations
- Schema changes (statements beginning with
ALTER) cannot currently be cancelled. However, to monitor the progress of schema changes, you can useSHOW JOBS. - In rare cases where a query is close to completion when a cancellation request is issued, the query may run to completion.
Required Privileges
The root user can cancel any currently active queries, whereas non-root users cancel only their own currently active queries.
Synopsis
Parameters
| Parameter | Description |
|---|---|
query_id |
A scalar expression that produces the ID of the query to cancel.CANCEL QUERY accepts a single query ID. If a subquery is used and returns multiple IDs, the CANCEL QUERY statement will therefore fail. |
Response
When a query is successfully cancelled, CockroachDB sends a query execution canceled error to the client that issued the query.
- If the canceled query was a single, stand-alone statement, no further action is required by the client.
- If the canceled query was part of a larger, multi-statement transaction, the client should then issue a
ROLLBACKstatement.
Examples
Cancel a Query via the Query ID
In this example, we use the SHOW QUERIES statement to get the ID of a query and then pass the ID into the CANCEL QUERY statement:
> SHOW QUERIES;
+----------------------------------+---------+----------+----------------------------------+----------------------------------+--------------------+------------------+-------------+-----------+
| query_id | node_id | username | start | query | client_address | application_name | distributed | phase |
+----------------------------------+---------+----------+----------------------------------+----------------------------------+--------------------+------------------+-------------+-----------+
| 14dacc1f9a781e3d0000000000000001 | 2 | mroach | 2017-08-10 14:08:22.878113+00:00 | SELECT * FROM test.kv ORDER BY k | 192.168.0.72:56194 | test_app | false | executing |
+----------------------------------+---------+----------+----------------------------------+----------------------------------+--------------------+------------------+-------------+-----------+
| 14dacc206c47a9690000000000000002 | 2 | root | 2017-08-14 19:11:05.309119+00:00 | SHOW CLUSTER QUERIES | 127.0.0.1:50921 | | NULL | preparing |
+----------------------------------+---------+----------+----------------------------------+----------------------------------+--------------------+------------------+-------------+-----------+
> CANCEL QUERY '14dacc1f9a781e3d0000000000000001';
Cancel a Query via a Subquery
In this example, we nest a SELECT clause that retrieves the ID of a query inside the CANCEL QUERY statement:
> CANCEL QUERY (SELECT query_id FROM [SHOW CLUSTER QUERIES]
WHERE client_address = '192.168.0.72:56194'
AND username = 'mroach'
AND query = 'SELECT * FROM test.kv ORDER BY k');
Note:
CANCEL QUERY accepts a single query ID. If subquery is used and returns multiple IDs, the CANCEL QUERY statement will therefore fail.See Also
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