CANCEL QUERY

The CANCEL QUERY statement is used to cancel a running query within the Firebolt engine. This statement provides a mechanism to terminate the execution of a specific query identified by its unique query_id.

Syntax

CANCEL QUERY WHERE query_id = '<query_id>';

Parameters

Example

CANCEL QUERY WHERE query_id = '12345';

Notes

• The query_id is typically obtained from the information_schema.engine_running_queries view.
• When a query is canceled, it terminates the processes of that specific query. This action both frees up resources and prevents any further execution of the query.
• This statement is designed for administrative use and may require appropriate privileges to execute. However, all users can cancel their own queries by default.

Example Use Case

Consider a scenario where there is a long-running query that needs to be canceled to free up system resources. The following statement can be used to obtain the query_id:

SELECT status, duration_usec, query_text, query_id FROM information_schema.engine_running_queries;

Suppose the long-running query is identified with query_id ‘12345’:

CANCEL QUERY WHERE query_id = '12345';

This will initiate the cancellation process for the specified query_id. While the query is not immediately removed from running_queries, its status will be observed as CANCELING there. After the cancellation process is completed, the query will have the CANCELED status in the information_schema.engine_query_history view:

SELECT query_id, query_text FROM information_schema.engine_query_history WHERE status = 'CANCELED';