postgres连接数常用指令

1、进入数据库

#sudo su - postgres
#psql

2、查询当前总共正在使用的连接数：

select count(1) from pg_stat_activity;

3、按照用户分组查看

select usename, count(*) from pg_stat_activity group by usename order by count(*) desc;

4、查询当前所有连接的状态

select datname,pid,application_name,state from pg_stat_activity;

5、显示系统允许的最大连接数

show max_connections;

6、修改最大连接数

alter system set max_connections= 5000

7、pg库连接数释放

SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE state='idle';