PostgreSQL 学习笔记014 —— PostgreSQL 常用命令（4）

查看表空间

postgres=# \db
       List of tablespaces
    Name    |  Owner   | Location
------------+----------+----------
 pg_default | postgres |
 pg_global  | postgres |
(2 rows)

postgres=# select * from pg_tablespace;
 oid  |  spcname   | spcowner | spcacl | spcoptions
------+------------+----------+--------+------------
 1663 | pg_default |       10 |        |
 1664 | pg_global  |       10 |        |
(2 rows)

查看数据库中所有表

postgres=# \dt
         List of relations
 Schema | Name  | Type  |  Owner
--------+-------+-------+----------
 public | test1 | table | postgres
 public | test2 | table | postgres
(2 rows)

查询表大小

postgres=# select pg_size_pretty(pg_relation_size('test1')) as size;
  size
---------
 0 bytes
(1 row)

-- 查询单个表的总大小，包括该表的索引大小
postgres=# select pg_size_pretty(pg_total_relation_size('test1')) as size;
  size
---------
 0 bytes
(1 row)

查询所有表大小

postgres=# select relname, pg_size_pretty(pg_relation_size(relid)) as size from pg_stat_user_tables;
 relname |  size
---------+---------
 test1   | 0 bytes
 test2   | 0 bytes
(2 rows)

-- 查询所有表的总大小，包括其索引大小
postgres=# select relname, pg_size_pretty(pg_total_relation_size(relid)) as size from pg_stat_user_tables;
 relname |  size
---------+---------
 test1   | 0 bytes
 test2   | 0 bytes
(2 rows)

切换用户

-- 使用\c - username表示数据库不变，只切换用户
postgres=# \c - user1;
You are now connected to database "postgres" as user "user1".

-- 以用户username切换到databasename的数据库
postgres=# \c testdb user1;
You are now connected to database "testdb" as user "user1".

查看当前数据库名称

postgres=# select current_database();
 current_database
------------------
 postgres
(1 row)