I see this in logs on server shutdown:

```
2022.01.30 02:51:22.856463 [ 755777 ] {} <Error> void DB::MergeTreeBackgroundExecutor<DB::MergeMutateRuntimeQueue>::routine(DB::TaskRuntimeDataPtr) [Queue = DB::MergeMutateRuntimeQueue]: Code: 236. DB::Exception: Cancelled merging parts.
```

but it's not an error.

Log level should be changed and it should not show stack trace.
: task(std::move(task_))
        , metric(metric_)
    {
        
        
        
        
        CurrentMetrics::values[metric].fetch_add(1);
    }
    ~TaskRuntimeData()
    {
        CurrentMetrics::values[metric].fetch_sub(1);
    }
    ExecutableTaskPtr task;
    CurrentMetrics::Metric metric;
    std::atomic_bool is_currently_deleting{false};
    
    
    
    Poco::Event is_done{false};
    
    UInt64 priority{0};
    
    static bool comparePtrByPriority(const TaskRuntimeDataPtr & lhs, const TaskRuntimeDataPtr & rhs)
    {
        return lhs->priority > rhs->priority;
    }
};
class OrdinaryRuntimeQueue