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第8天 | openGauss中一个数据库可以存储在多个表空间中

news 2025/7/19 7:04:31

接着昨天继续学习openGauss,今天是第8天了。今天学习内容是o一个数据库可以存储在多个表空间中。
老规矩，先登陆墨天轮为我准备的实训实验室

root@modb:~# su - omm
omm@modb:~$ gsql -r

作业要求

1.创建表空间newtbs1、 ds_location1，查看表空间

omm=# CREATE TABLESPACE newtbs1 RELATIVE LOCATION 'tablespace/tablespace_1';
CREATE TABLESPACE
omm=# CREATE TABLESPACE ds_location1  RELATIVE LOCATION 'tablespace/test_ts1';
omm=# CREATE TABLESPACE

–执行下面的命令，查看当前表空间：

omm=# \dbList of tablespacesName     | Owner |        Location         
--------------+-------+-------------------------ds_location1 | omm   | tablespace/test_ts1newtbs1      | omm   | tablespace/tablespace_1pg_default   | omm   | pg_global    | omm   | 
(4 rows)

2.创建一个数据库newdb1，默认表空间为newtbs1

omm=# CREATE DATABASE newdb1 WITH TABLESPACE = newtbs1;
CREATE DATABASE

####　3.创建用户user5，并授予SYSADMIN权限，访问数据库newdb1，在表空间ds_location1上，创建一个表newt1（表结构自定义）

omm=# CREATE USER user5 IDENTIFIED BY 'user5@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# ALTER USER user5 SYSADMIN;
omm=# ALTER ROLE
omm-# \c newdb1 user5
Password for user user5: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "newdb1" as user "user5".
newdb1=> create table newt1 (col1 char(10)) tablespace ds_location1;
CREATE TABLE

4.查看表所在的表空间

newdb1=> select * from pg_tables where tablename = 'newt1';schemaname | tablename | tableowner |  tablespace  | hasindexes | hasrules | hastriggers | tablecr
eator |            created            |         last_ddl_time         
------------+-----------+------------+--------------+------------+----------+-------------+--------
------+-------------------------------+-------------------------------public     | newt1     | user5      | ds_location1 | f          | f        | f           | user5  | 2022-12-01 10:14:27.780919+08 | 2022-12-01 10:14:27.780919+08
(1 row)

5.查看表空间newtbs1、 ds_location1上的对象

查看表空间 ds_location1的对象

newdb1=> select relname, relkind, relpages,pg_size_pretty(pg_relation_size(a.oid)),reltablespace,relowner  
newdb1-> newdb1-> from pg_class a, pg_tablespace tb  
where a.relkind in ('r', 'i')  
newdb1-> and a.reltablespace=tb.oid  
newdb1-> and tb.spcname='ds_location1'  
newdb1-> order by a.relpages desc;relname | relkind | relpages | pg_size_pretty | reltablespace | relowner 
---------+---------+----------+----------------+---------------+----------newt1   | r       |        0 | 0 bytes        |         16390 |    16392
(1 row)

查看表空间newtbs1的对象

select relname, relkind, relpages,pg_size_pretty(pg_relation_size(a.oid)),reltablespace,relowner  
from pg_class a, pg_tablespace tb  
where a.relkind in ('r', 'i')  
and a.reltablespace=tb.oid  
and tb.spcname='newtbs1'  
order by a.relpages desc;