If the merge was interrupted by, for

If the merge was interrupted by, for example, a memory limit, the merge mutate background executor will call cancel on the merge task without a lock, but, in this case, the partially created resulting part will not be removed (since it was not finished and at this stage was not visible). After that, the merge task will be destroyed, which will trigger the destruction of the resulting part. This will revert the disk transaction and cause the data to be removed from S3. At the end, this garbage cleanup was executed under the merge mutate background executor lock. #89875 (Mikhail Artemenko).