PostgreSQL Error: sorry, too many clients already

Error

PG的默认最大连接数是100.

如果超过100就会报错sorry, too many clients already

Find

show max_connections;
SELECT COUNT(*) from pg_stat_activity;
SELECT * FROM pg_stat_activity;

Solution

1. 提高最大连接数

ALTER SYSTEM SET max_connections
然后重启pg

2. 查看程序，减少从未关闭连接的函数
3. 修改事务时间，减少事务未提交带来的问题

SET statement_timeout = 50000;   # 此处设置成50秒