创建数据库bbb且owner为用户b：

postgres9.6@[local]:5432 postgres# create database bbb owner b;CREATE DATABASETime: 259.099 ms

默认情况下使用用户c也可以连接数据库bbb：

postgres9.6@[local]:5432 postgres# \c bbb cYou are now connected to database "bbb" as user "c".

回收public的connect on database bbb权限：

c@[local]:5432 bbb# \c postgres postgres9.6You are now connected to database "postgres" as user "postgres9.6".postgres9.6@[local]:5432 postgres# revoke connect on database bbb from public;REVOKETime: 2.088 ms

此时用户c没有了连接数据库bbb的权限：

postgres9.6@[local]:5432 postgres# \c bbb cFATAL: permission denied for database "bbb"DETAIL: User does not have CONNECT privilege.Previous connection kept

但bbb数据库的owner用户b可以连接数据库：

postgres9.6@[local]:5432 postgres# \c bbb bYou are now connected to database "bbb" as user "b".b@[local]:5432 bbb#

此种情况下超级用户也可以连接该数据库：

b@[local]:5432 bbb# \c bbb postgres9.6You are now connected to database "bbb" as user "postgres9.6".postgres9.6@[local]:5432 bbb# postgres9.6@[local]:5432 bbb# \du List of roles Role name | Attributes | Member of -------------+------------------------------------------------------------+----------- a | | {} b | | {} c | | {} postgres9.6 | Superuser, Create role, Create DB, Replication, Bypass RLS | {}

另外一种方法：从pg_hba.conf中限定：

# TYPE DATABASE USER ADDRESS METHOD# "local" is for Unix domain socket connections onlylocal all all trust # IPv4 local connections:host all all 127.0.0.1/32 trust...#host all all 0.0.0.0/0 md5

补充：Postgres限制每个用户只能连接指定数量的session，防止服务器资源紧张

限制每个用户只能连接指定数量的session，防止服务器资源紧张

（1）创建测试用户test:

highgo=#create user test;CREATEROLEhighgo=#\du List of roles Role name | Attributes | Member of-----------+------------------------------------------------+---------- highgo | Superuser, Create role, Create DB, Replication | {} test | | {}

（2）设置仅允许用户test使用一个连接

highgo=#ALTER ROLE test CONNECTION LIMIT 1;ALTERROLE

（3）在session 1中使用test用户连接highgo数据库

highgo=>\c highgo testYouare now connected to database "highgo" as user "test".highgo=>

（4）在session 2中也使用test用户连接highgo数据库，会出现如下错误：

highgo=#\c highgo test致命错误: 由角色"test"发起的连接太多了Previousconnection kept

（5）查询用户test链接限制

highgo=>SELECT rolconnlimit FROM pg_roles WHERE rolname = 'test'; rolconnlimit-------------- 1(1row)

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。