设置 max_prepared_stmt_count 失败时提示更详细

internal/nodes/api_node.go

@@ -293,7 +293,10 @@ func (this *APINode) setupDB() error {
 			if valueInt < 65535 {
 				_, err := db.Exec("SET GLOBAL max_prepared_stmt_count=65535")
 				if err != nil {
-					return err
+					return errors.New("run 'SET GLOBAL max_prepared_stmt_count' on database failed: " + err.Error() + ", \nyou can change the variable in 'my.cnf': \n~~~\n" + `[mysqld]
+max_prepared_stmt_count=65535
+~~~
+then restart mysqld.`)
 				}
 			}
 		}