MS-577 Unittest Query randomly hung

Former-commit-id: 9cd7008c1b47edb7b4287a9102681631c9128169

cpp/CHANGELOG.md

@@ -5,6 +5,7 @@ Please mark all change in change log and use the ticket from JIRA.
 # Milvus 0.5.0 (TODO)
 
 ## Bug
+- MS-577 - Unittest Query randomly hung
 
 ## Improvement
 - MS-552 - Add and change the easylogging library

cpp/src/scheduler/JobMgr.cpp

@@ -32,8 +32,8 @@ JobMgr::JobMgr(ResourceMgrPtr res_mgr)
 void
 JobMgr::Start() {
     if (not running_) {
-        worker_thread_ = std::thread(&JobMgr::worker_function, this);
         running_ = true;
+        worker_thread_ = std::thread(&JobMgr::worker_function, this);
     }
 }