Cancelling by workflowRunIds is synchronous, and cancelled is the exact number of workflow runs cancelled.
A filter-based cancel (including cancelling all workflow runs) is tracked as a bulk action and runs in the background:
- By default, the request waits up to one minute for the bulk action to finish. If it does not finish in time, a
429is returned, and the bulk action keeps running in the background. - With
async=true, the request returns right after the bulk action is created, together with itsactionId. You can follow its progress with Get a Bulk Action. cancelledis the number of in-progress workflow runs that matched the filters when the request was accepted, not the number of workflow runs actually cancelled.- Sending the same filters again while an identical bulk action is still in progress does not start a new one. The in-progress bulk action is returned instead.
- Up to 1000 bulk actions can be in progress at the same time. Beyond that, a
412is returned.