TCP keepalive可用于： 1、使网络连接处于活跃（相对于Idle而言）状态 2、检测在没有关闭网络连接情况下的通信中断 本节介绍OS和PG的相关参数说明和配置。 **OS配置** ``` keepalive idle time: tpc连接处于空闲状态下，超过该时间则发送keepalive packet；2 hours on both Linux and Windows keepalive interval: 如keepalive packet没有应答，则在间隔后再次发送packet；75 seconds on Linux, 1 second on Windows keepalive count: 发送packet的次数；9 on Linux, 10 on Windows (this value cannot be changed on Windows) ``` 在Linux中，可通过如下配置 ``` # On Linux, this is done by editing the /etc/sysctl.conf file: # detect dead connections after 70 seconds net.ipv4.tcp_keepalive_time = 60 net.ipv4.tcp_keepalive_intvl = 5 net.ipv4.tcp_keepalive_probes = 3 ``` 使用命令生效 ``` sysctl -p ``` **PG参数配置** ``` keepalives_idle：为0则使用OS配置 keepalives_interval：为0则使用OS配置 keepalives_count：为0则使用OS配置 ``` **参考资料** [TCP keepalive for a better PostgreSQL experience](https://www.cybertec-postgresql.com/en/tcp-keepalive-for-a-better-postgresql-experience/) [LIBPQ-KEEPALIVES-IDLE](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-KEEPALIVES-IDLE)