Add important log (#694)

* #670 Random failure of unittest db_test::SEARCH_TEST

* add an important log

* add an important log

* add an important log

core/src/db/engine/ExecutionEngineImpl.cpp

@@ -603,7 +603,7 @@ ExecutionEngineImpl::Search(int64_t n, const float* data, int64_t k, int64_t npr
     }
 
     if (!status.ok()) {
-        ENGINE_LOG_ERROR << "Search error";
+        ENGINE_LOG_ERROR << "Search error:" << status.message();
     }
     return status;
 }

core/src/scheduler/task/BuildIndexTask.cpp

@@ -86,7 +86,7 @@ XBuildIndexTask::Load(milvus::scheduler::LoadType type, uint8_t device_id) {
 
         size_t file_size = to_index_engine_->PhysicalSize();
 
-        std::string info = "Load file id:" + std::to_string(file_->id_) + " " + type_str +
+        std::string info = "Build index task load file id:" + std::to_string(file_->id_) + " " + type_str +
                            " file type:" + std::to_string(file_->file_type_) + " size:" + std::to_string(file_size) +
                            " bytes from location: " + file_->location_ + " totally cost";
         double span = rc.ElapseFromBegin(info);

core/src/scheduler/task/SearchTask.cpp

@@ -160,7 +160,7 @@ XSearchTask::Load(LoadType type, uint8_t device_id) {
 
     size_t file_size = index_engine_->PhysicalSize();
 
-    std::string info = "Load file id:" + std::to_string(file_->id_) +
+    std::string info = "Search task load file id:" + std::to_string(file_->id_) + " " + type_str +
                        " file type:" + std::to_string(file_->file_type_) + " size:" + std::to_string(file_size) +
                        " bytes from location: " + file_->location_ + " totally cost";
     double span = rc.ElapseFromBegin(info);