HPCC-29923 Avoid CRowServer cancel if not running

This avoids an inherent delay being introduced by the MP layer. CRowServer is used by Global Group, Global TopN and a refactoring form of IndexWrite (where is merges down to less parts). Signed-off-by: Jake Smith <[email protected]>
hpcc-systems · Jul 12, 2023 · beba95a · beba95a
1 parent 242ab8d
commit beba95a
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/thorlcr/thorutil/thormisc.cpp b/thorlcr/thorutil/thormisc.cpp
@@ -1371,8 +1371,12 @@ class CRowServer : public CSimpleInterface, implements IThreaded, implements IRo
 #ifdef TRACE_GLOBAL_GROUP
         ActPrintLog(activity, "%s", __func__);
 #endif
-        running = false;
-        comm.cancel(RANK_ALL, mpTag);
+        bool wanted = true;
+        if (running.compare_exchange_strong(wanted, false))
+        {
+            running = false;
+            comm.cancel(RANK_ALL, mpTag);
+        }
     }
 };