Don't wait in scheduler queue if all workers out. (#8002)

Author: Tony-Romanov

ydb/library/yql/providers/dq/global_worker_manager/global_worker_manager.cpp

@@ -781,7 +781,15 @@ class TGlobalWorkerManager: public TWorkerManagerCommon<TGlobalWorkerManager> {
     }
 
     void TryResume() {
-        if (Workers.FreeSlots() >= ScheduleWaitCount) {
+        if (!Workers.Capacity() && ScheduleWaitCount > 0U) {
+            Scheduler->ProcessAll([&] (const auto& item) {
+                Send(item.Sender, new TEvAllocateWorkersResponse("All workers shutted down", NYql::NDqProto::StatusIds::OVERLOADED));
+                return true;
+            });
+
+            ScheduleWaitCount = 0U;
+            DeadOperations.clear();
+        } else if (Workers.FreeSlots() >= ScheduleWaitCount) {
             Scheduler->Process(Workers.Capacity(), Workers.FreeSlots(), [&] (const auto& item) {
                 auto maybeDead = DeadOperations.find(item.Request.GetResourceId());
                 if (maybeDead != DeadOperations.end()) {