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

MS-328 Check metric type on server start

See merge request megasearch/milvus!316

Former-commit-id: 135d8bcfcc4638866dfed8bdfc896b5db9e8fecf

cpp/CHANGELOG.md

@@ -44,6 +44,7 @@ Please mark all change in change log and use the ticket from JIRA.
 - MS-305 - Add CPU core percent metric
 - MS-310 - Add milvus CPU utilization ratio and CPU/GPU temperature metrics
 - MS-324 - Show error when there is not enough gpu memory to build index
+- MS-328 - Check metric type on server start
 
 ## New Feature
 - MS-180 - Add new mem manager

cpp/src/server/DBWrapper.cpp

@@ -74,6 +74,12 @@ DBWrapper::DBWrapper() {
         }
     }
 
+    std::string metric_type = engine_config.GetValue(CONFIG_METRICTYPE, "L2");
+    if(metric_type != "L2" && metric_type != "IP") {
+        std::cout << "ERROR! Illegal metric type: " << metric_type << ", available options: L2 or IP" << std::endl;
+        kill(0, SIGUSR1);
+    }
+
     //set archive config
     engine::ArchiveConf::CriteriaT criterial;
     int64_t disk = db_config.GetInt64Value(CONFIG_DB_ARCHIVE_DISK, 0);
@@ -101,6 +107,7 @@ DBWrapper::DBWrapper() {
         }
     }
 
+    //create db instance
     std::string msg = opt.meta.path;
     try {
         zilliz::milvus::engine::DB::Open(opt, &db_);