Postgresql 连接数查看，死锁问题解决

-- 查看所有连接
select * -- datname,pid,application_name,state 
from pg_stat_activity;
-- 查询最大连接数
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;
show max_connections; -- 192-- 查询超级用户连接数
show superuser_reserved_connections;-- 杀掉空闲进程
select 'select pg_terminate_backend('||pid||');' as terminate_script,datname,pid,application_name,state,client_addr,query
from pg_stat_activity
where state = 'idle'
and usename = 'tzq'
order by client_addr;-- 检索死锁进程IDselect * from pg_stat_activity where datname='tzydb' and wait_event_type='Lock';select pid,query,* from pg_stat_activity where datname='vulnerability-management' and wait_event_type = 'Lock';-- 找到对用的pid列的值或
-- oid是每个表隐藏的idselect oid from pg_class where relname='可能锁表了的表' select pid from pg_locks where relation='上面查出的oid'-- 将进程杀掉select pg_cancel_backend("死锁那条数据的pid值")；