MaxScale:检索数据库名称失败

Question

当我启动maxscale时，我得到以下错误：

...
2017-01-17 20:26:05   debug  : qc_sqlite: Token 34 not handled explicitly.
2017-01-17 20:26:05   debug  : qc_sqlite: Token 103 not handled explicitly.
2017-01-17 20:26:05   debug  : qc_sqlite: Token 216 not handled explicitly.
2017-01-17 20:26:05   notice : Loaded module maxscaled: V2.0.0 from /usr/lib64/maxscale/libmaxscaled.so
2017-01-17 20:26:05   notice : Listening connections at /tmp/maxadmin.sock with protocol MaxScale Admin
2017-01-17 20:26:05   debug  : 140414757828672 [poll_add_dcb] Added dcb 0x1ad27f0 in state DCB_STATE_LISTENING to poll set.
2017-01-17 20:26:05   notice : Using encrypted passwords. Encryption key: '/var/lib/maxscale/.secrets'.
2017-01-17 20:26:05   error  : Failed to retrieve database names:
2017-01-17 20:26:05   error  : Shard Router: Unable to load database grant information, MaxScale authentication will proceed without including database permissions. See earlier error messages for user '*******' for more information.
2017-01-17 20:26:05   error  : Failed to retrieve database names:
2017-01-17 20:26:05   error  : Shard Router: Unable to load database grant information, MaxScale authentication will proceed without including database permissions. See earlier error messages for user '*******' for more information.

我启用了调试，但仍然看不到“早期”消息是什么！！我可以使用已配置的帐户连接到服务器，并且可以毫无问题地运行显示数据库。

数据库在RDS中。

有什么想法吗？

谢谢

Answer 1

maxscale是否能够运行"show database“并不重要，它需要在运行时显式地授予show database权限：

SELECT * 
FROM   ( 
   ( 
          SELECT Count(1) AS ndbs 
          FROM   information_schema.schemata) AS tbl1, 
   ( 
          SELECT grantee, 
                 privilege_type 
          FROM   information_schema.user_privileges 
          WHERE  privilege_type='SHOW DATABASES' 
          AND    REPLACE(grantee, '\'','')=CURRENT_USER()) AS tbl2);

因此，如果不专门授予priv，查询将不会返回任何内容。

Answer 2

MaxScale Tutorial中描述了MaxScale用户的授权要求。

maxuser@%用户所需的授权包括：

GRANT SELECT ON mysql.user TO 'maxuser'@'%';
GRANT SELECT ON mysql.db TO 'maxuser'@'%';
GRANT SELECT ON mysql.tables_priv TO 'maxuser'@'%';
GRANT SHOW DATABASES ON *.* TO 'maxuser'@'%';
GRANT REPLICATION CLIENT ON *.* TO 'maxuser'@'%';