Merge branch 'branch-0.3.1' into 'branch-0.3.1'

increse thrift thread count

See merge request megasearch/milvus!227

Former-commit-id: 6e307b269d0ebb15ae08ac61cd720e3d2733ba61

cpp/src/server/MilvusServer.cpp

@@ -76,7 +76,7 @@ MilvusServer::StartService() {
             return;
         }
 
-        stdcxx::shared_ptr<ThreadManager> threadManager(ThreadManager::newSimpleThreadManager());
+        stdcxx::shared_ptr<ThreadManager> threadManager(ThreadManager::newSimpleThreadManager(16));
         stdcxx::shared_ptr<PosixThreadFactory> threadFactory(new PosixThreadFactory());
         threadManager->threadFactory(threadFactory);
         threadManager->start();