Set up docs MCP更改角色。
语法：
ALTER ROLE [IF EXISTS] name1 [RENAME TO new_name |, name2 [,...]]
[ON CLUSTER cluster_name]
[DROP ALL PROFILES]
[DROP ALL SETTINGS]
[DROP PROFILES 'profile_name' [,...] ]
[DROP SETTINGS variable [,...] ]
[ADD|MODIFY SETTINGS variable [= value] [MIN [=] min_value] [MAX [=] max_value] [CONST|READONLY|WRITABLE|CHANGEABLE_IN_READONLY] | PROFILE 'profile_name'] [,...]
[SET variable [= value] [MIN [=] min_value] [MAX [=] max_value] [CONST|READONLY|WRITABLE|CHANGEABLE_IN_READONLY] [,...] ]
[ADD PROFILES 'profile_name' [,...] ]SET variable = value 是 MODIFY SETTING variable = value 的别名：它会就地修改单个设置，同时保留其余设置；而不带修饰的 SETTINGS 子句会替换整个 settings 列表，并移除所有继承的 (父级) profile。
属于： ALTER
相关： CREATE ROLE, ALTER, SET ROLE, GRANT