postgresql通常遇到这种报错都是连接池满了的原因：



1   查询当前所有连接的状态


select datname,pid,application_name,state from pg_stat_activity;


2  查看数据库剩余连接数：


select max_conn-now_conn as resi_conn from (select setting::int8 as max_conn,(select count(*) from pg_stat_activity) as now_conn from pg_settings where name = 'max_connections') t;

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3  查看为超级用户保留的连接数:-----show superuser_reserved_connections;

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​psql: FATAL:  53300: sorry, too many clients already

数据库连接已满，无法建立新的连接

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4   关闭空闲连接

查看目前所有的连接的进程id、应用名称、状态---select datname,pid,application_name,state from pg_stat_activity; 

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通过pid终止空闲连接----​select pg_terminate_backend(pid) from pg_stat_activity; 

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​5   当前总共正在使用的连接数----select count(1) from pg_stat_activity;

显示系统允许的最大连接数----show max_connections;

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