--當(dāng)前總共正在使用的連接數(shù)
postgres=# select count(1) from pg_stat_activity;
 
--顯示系統(tǒng)允許的最大連接數(shù)
postgres=# show max_connections;
 
--顯示系統(tǒng)保留的用戶數(shù)
postgres=# show superuser_reserved_connections ;

--按照用戶分組查看
select usename, count(*) from pg_stat_activity group by usename order by count(*) desc;