postgresql数据库基本信息查看

切换至postgresql数据库用户pguser 或 postgres（根据自己实际情况）

1. 1 SELECT version();

２.对的

2. 查看数据库大小：

1 SELECT pg_size_pretty(pg_database_size('tianrun')) As fulldbsize;

3. 查看所有的数据库的大小：

1 select pg_database.datname, pg_size_pretty (pg_database_size(pg_database.datname)) AS size from pg_database;

4. 查看各数据库数据创建时间：

1 select datname,(pg_stat_file(format('%s/%s/PG_VERSION', 
2 case 
3 when spcname='pg_default' then 'base' 
4 else 'pg_tblspc/'||t2.oid||'/PG_11_201804061/' 
5 end, 
6 t1.oid))).* 
7 from pg_database t1,pg_tablespace t2 where t1.dattablespace=t2.oid;

5.按占空间大小，顺序查看所有表的大小

1 select relname, pg_size_pretty(pg_relation_size(relid)) from pg_stat_user_tables where schemaname='public' order by pg_relation_size(relid) desc;

6. 按占空间大小，顺序查看索引大小

1 select indexrelname, pg_size_pretty(pg_relation_size(relid)) from pg_stat_user_indexes where schemaname='public' order by pg_relation_size(relid) desc;