Merge pull request #42874 from azat/query-hung-on-cancel-fix

src/Processors/Executors/ExecutingGraph.cpp

@@ -109,6 +109,13 @@ bool ExecutingGraph::expandPipeline(std::stack<uint64_t> & stack, uint64_t pid)
 
     {
         std::lock_guard guard(processors_mutex);
+        /// Do not add new processors to existing list, since the query was already cancelled.
+        if (cancelled)
+        {
+            for (auto & processor : new_processors)
+                processor->cancel();
+            return false;
+        }
         processors->insert(processors->end(), new_processors.begin(), new_processors.end());
     }
 
@@ -388,6 +395,7 @@ void ExecutingGraph::cancel()
     std::lock_guard guard(processors_mutex);
     for (auto & processor : *processors)
         processor->cancel();
+    cancelled = true;
 }
 
 }

src/Processors/Executors/ExecutingGraph.h

@@ -157,6 +157,7 @@ private:
     UpgradableMutex nodes_mutex;
 
     const bool profile_processors;
+    bool cancelled = false;
 };
 
 }