psql 进入命令模式

一、查看连接用户

SELECT  
    pg_terminate_backend(procpid)  
FROM  
    pg_stat_activity  
WHERE -- don't kill my own connection! 
    procpid <> pg_backend_pid(); 

二、回收用户权限

dbname：需你指定数据库的名称

username：连接用户

REVOKE CONNECT ON DATABASE dbname FROM PUBLIC,username;