PostgreSQL操作随记

PostgreSQL默认用户: postgres

Connect

psql -h host -U user -W

连接数相关

配置文件

sed  "s/max_connections = .*/max_connections = 1024/" /var/lib/postgresql/data/postgresql.conf|grep max_connection

sed -i "s/max_connections = .*/max_connections = 1024/" /var/lib/postgresql/data/postgresql.conf|grep max_connection

commands

临时修改连接数(待验证)

alter system set max_connections=1024

查看连接数

select count(1) from pg_stat_activity;

查看最大连接数值

show max_connections;

查看保留连接数

show superuser_reserved_connections;

查看连接的客户端信息

SELECT * FROM pg_stat_activity

keywords: PSQLException: FATAL: sorry, too many clients already

common commands

show databases in psql

SELECT datname FROM pg_database;