一、问题：
mysql从5.1升级到5.6后，创建新用户，进行grant赋权的时候，报错：
ERROR 2013 (HY000): Lost connection to MySQL server during query
操作系统为：centOS6.5，原自带的版本为5.1.
二、分析
在网上搜到一帖子（http://www.111cn.net/database/mysql/79899.htm）
官网下面看mysql 5.6升级指南，其中有这么一段：
After upgrading to a new version of MySQL, run mysql_upgrade (see Section 4.4.7, “mysql_upgrade — Check and Upgrade MySQL Tables”). This program checks your tables, and attempts to repair them if necessary. It also updates your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. (Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features.)
mysql_upgrade does not upgrade the contents of the help tables. For upgrade instructions, see Section 5.1.10, “Server-Side Help”.
mysql_upgrade should not be used when the server is running with –gtid-mode=ON, since it may make changes in nontransactional system tables in the mysql database, many of which are MyISAM and cannot be changed to use a different storage engine. See GTID mode and mysql_upgrade.
版本更新后，需要重新更新相关的表和权限信息。
三、处理
1)、执行：mysql_upgrade -u root -p
2)、重新执行grant语句