Fix lock in case of query was cancelled.

dbms/programs/server/TCPHandler.cpp

@@ -514,6 +514,10 @@ void TCPHandler::processOrdinaryQueryWithProcessors(size_t num_threads)
                 {
                     /// A packet was received requesting to stop execution of the request.
                     executor->cancel();
+                    /// Clear queue in case if somebody is waiting lazy_format to push.
+                    lazy_format->finish();
+                    lazy_format->clearQueue();
+
                     break;
                 }
                 else

dbms/src/Processors/Formats/LazyOutputFormat.h

@@ -26,8 +26,16 @@ public:
 
     void setRowsBeforeLimit(size_t rows_before_limit) override;
 
+    void finish() { finished_processing = true; }
+    void clearQueue() { queue.clear(); }
+
 protected:
-    void consume(Chunk chunk) override { queue.emplace(std::move(chunk)); }
+    void consume(Chunk chunk) override
+    {
+        if (!finished_processing)
+            queue.emplace(std::move(chunk));
+    }
+
     void consumeTotals(Chunk chunk) override { totals = std::move(chunk); }
     void consumeExtremes(Chunk chunk) override { extremes = std::move(chunk); }
 

dbms/src/Processors/NullSink.h

@@ -15,6 +15,8 @@ public:
         inputs.front().close();
         return Status::Finished;
     }
+
+    InputPort & getPort() { return inputs.front(); }
 };
 
 }