$ i=0; while ./clickhouse benchmark -c 30 --timelimit=3 -d0 --cumulative --query "select * from remote('127.{2,3}', system, one)"; do echo Iteration=$i; ((i+=1)); done
Loaded 1 queries.

digraph
{
  rankdir="LR";
  { node [shape = box]
    n140624128624664[label="Remote(10 jobs) (Async)"];
    n140627179876376[label="Remote(11 jobs) (Finished)"];
    n140624730927768[label="ExpressionTransform(5 jobs) (NeedData)"];
    n140624152969048[label="ExpressionTransform(5 jobs) (Finished)"];
    n140624165957208[label="Resize(0 jobs) (NeedData)"];
    n140624293623256[label="LimitsCheckingTransform(10 jobs) (NeedData)"];
    n140627179694168[label="NullSource(0 jobs) (NeedData)"];
    n140624245605656[label="NullSource(0 jobs) (NeedData)"];
    n140624145010712[label="LazyOutputFormat(10 jobs) (NeedData)"];
  }
  n140624128624664 -> n140624730927768;
  n140627179876376 -> n140624152969048;
  n140624730927768 -> n140624165957208;
  n140624152969048 -> n140624165957208;
  n140624165957208 -> n140624293623256;
  n140624293623256 -> n140624145010712;
  n140627179694168 -> n140624145010712;
  n140624245605656 -> n140624145010712;
}

WITH
    arrayMap(x -> demangle(addressToSymbol(x)), trace) AS trace_array,
    arrayStringConcat(trace_array, '\n') AS trace_string
SELECT
    thread_id,
    trace_string
FROM system.stack_trace
WHERE thread_id IN
(
    SELECT thread_id
    FROM system.processes
    ARRAY JOIN thread_ids AS thread_id
    WHERE query NOT LIKE '%system.%'
)

Row 1:
──────
thread_id:    6490
trace_string: pthread_cond_wait@@GLIBC_2.3.2
std::__1::condition_variable::wait(std::__1::unique_lock<std::__1::mutex>&)
DB::PipelineExecutor::executeStepImpl(unsigned long, unsigned long, std::__1::atomic<bool>*)
void std::__1::__function::__policy_invoker<void ()>::__call_impl<>(std::__1::__function::__policy_storage const*)
ThreadPoolImpl<std::__1::thread>::worker(std::__1::__list_iterator<std::__1::thread, void*>)
void* std::__1::__thread_proxy<>(void*)
start_thread
__clone

Row 2:
──────
thread_id:    6537
trace_string: pthread_cond_wait@@GLIBC_2.3.2
std::__1::condition_variable::wait(std::__1::unique_lock<std::__1::mutex>&)
DB::PipelineExecutor::executeStepImpl(unsigned long, unsigned long, std::__1::atomic<bool>*)
void std::__1::__function::__policy_invoker<void ()>::__call_impl<>(std::__1::__function::__policy_storage const*)
ThreadPoolImpl<std::__1::thread>::worker(std::__1::__list_iterator<std::__1::thread, void*>)
void* std::__1::__thread_proxy<>(void*)
start_thread
__clone

Row 3:
──────
thread_id:    6552
trace_string:
epoll_wait
DB::Epoll::getManyReady(int, epoll_event*, bool) const
DB::PollingQueue::wait(std::__1::unique_lock<std::__1::mutex>&)
DB::PipelineExecutor::executeImpl(unsigned long)
DB::PipelineExecutor::execute(unsigned long)
void std::__1::__function::__policy_invoker<void ()>::__call_impl<>(std::__1::__function::__policy_storage const*)
ThreadPoolImpl<std::__1::thread>::worker(std::__1::__list_iterator<std::__1::thread, void*>)
void* std::__1::__thread_proxy<>(void*)
start_thread
__clone

Row 4:
──────
thread_id:    31278
trace_string: pthread_cond_timedwait@@GLIBC_2.3.2
Poco::SemaphoreImpl::waitImpl(long)
ConcurrentBoundedQueue<DB::Chunk>::tryPop(DB::Chunk&, unsigned long)
DB::LazyOutputFormat::getChunk(unsigned long)
DB::PullingAsyncPipelineExecutor::pull(DB::Chunk&, unsigned long)
DB::PullingAsyncPipelineExecutor::pull(DB::Block&, unsigned long)
DB::TCPHandler::processOrdinaryQueryWithProcessors()
DB::TCPHandler::runImpl()
DB::TCPHandler::run()
Poco::Net::TCPServerConnection::start()
Poco::Net::TCPServerDispatcher::run()
Poco::PooledThread::run()
Poco::ThreadImpl::runnableEntry(void*)
start_thread
__clone

context->condvar.wait(lock, [&]
{
    return finished || context->wake_flag;
});

task_queue = {
  queues = size=2 {
    [0] = size=0 {}
    [1] = size=0 {}
  }
  num_tasks = 0
}

async_task_queue = {
  epoll = {
    epoll_fd = 271
    events_count = {
      Value = 2
    }
    fd_description = "epoll"
  }
  pipe_fd = ([0] = 321, [1] = 324)
  is_finished = {
    Value = false
  }
  tasks = size=1 {
    [0] = {
      __cc = {
        first = 139970762314112
        second = (thread_num = 0, data = 0x00007f4d7b911180, fd = 82)
      }
    }
  }
}

num_waiting_async_tasks = 0
threads_queue = {
  stack = size=2 {
    [0] = 1
    [1] = 0
  }
  thread_pos_in_stack = size=2 {
    [0] = 1
    [1] = 0
  }
  stack_size = 2
}