如何查询postgresql数量？

1、查询数据库版本

select version(); 2、查询数据库的运行时间

select current_timestamp-pg_postmaster_start_time() as uptime; 3、查询数据库的数据量

SELECT

datname ,

a.rolname ,

pg_encoding_to_char(encoding) ,

datcollate ,

datctype ,

pg_size_pretty(pg_database_size(datname)) FROM

pg_database d ,

pg_authid a WHERE

d.datdba = a.oid

AND datname NOT IN ('template0' ,'template1' ,'postgres' ) ORDER BY

pg_database_size(datname) DESC; 4、 查询手游数据库连接数使用情况如果相对electron有更多直观理解的, 也可以参考其格式如下:

www.diuxie.com

SELECT

s.setting "可用连接数"       ,

a.used_session "已使用连接数" ,

s.setting::bigintwww.diuxie.com - a.used_session "剩余连接数"

FROM

pg_settings s,

(

        SELECT

                COUNT(*) AS used_session

        FROM

                pg_stat_activity) a

WHERE

s.name='max_connections';

5、查询数据库参数配置

select name,setting,unit from pg_settings; 6、查询当前数据库

select current_database();