prepare system to withstand high load

docker-compose.yml

@@ -9,6 +9,7 @@ services:
     restart: unless-stopped
     volumes:
       - ./data:/var/lib/mysql
+    command: --max_connections=2000
   # this container's job is to initialize MySQL database. It should run just 1 time.
   databunker-init:
     #build: .

src/storage/mysql-storage.go

@@ -492,13 +492,16 @@ func (dbobj MySQLDB) getRecordInTableDo(q string, values []interface{}) (bson.M,
 	}
 	defer tx.Rollback()
 	rows, err := tx.Query(q, values...)
-	if err == sql.ErrNoRows {
-		return nil, nil
-	} else if err != nil {
+	if err != nil {
+		if rows != nil {
+			rows.Close()
+		}
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
 		return nil, err
 	}
 	defer rows.Close()
-
 	flag := rows.Next()
 	if flag == false {
 		fmt.Printf("no result, flag: %t\n", flag)

src/users_api.go

@@ -146,7 +146,7 @@ func (e mainEnv) userGet(w http.ResponseWriter, r *http.Request, ps httprouter.P
 		event.Record = userTOKEN
 	}
 	if err != nil {
-		returnError(w, r, "internal error", 405, nil, event)
+		returnError(w, r, "internal error", 405, err, event)
 		return
 	}
 	authResult = e.enforceAuth(w, r, event)