第9天 | openGauss中一个表空间可以存储多个数据库

学习目标

进一步学习表空间与数据库对象的关系，了解oid的含义。

课程学习

1.创建表空间、多个数据库和用户

#第一次进入等待15秒
#数据库启动中...
su - omm
gsql -r

--进入数据库omm，创建表空间、测试数据库
drop DATABASE  IF EXISTS  musicdb;
drop DATABASE  IF EXISTS  musicdb1;
drop DATABASE  IF EXISTS  musicdb2;
drop DATABASE  IF EXISTS  musicdb3;
drop tablespace IF EXISTS music_tbs;
drop tablespace IF EXISTS ds_location1;


omm=# CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE TABLESPACE
omm=#CREATE DATABASE musicdb  WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# CREATE DATABASE musicdb1 WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# CREATE DATABASE musicdb2 WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# CREATE DATABASE musicdb3 WITH TABLESPACE = music_tbs;
CREATE DATABASE

--执行下面的SQL语句，创建用户user1 ：
drop user  IF EXISTS  user1;

omm=# CREATE USER user1 IDENTIFIED BY 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
  
--授予user1数据库系统的SYSADMIN权限：
omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE

2.使用sql查看数据库所在的表空间

--查看数据库所在的表空间，可以看到一个表空间可以有多个数据库

omm=# select datname,dattablespace,spcname from pg_database d, pg_tablespace t where d.dattablespace=t.oid order by spcname;   
  datname  | dattablespace |  spcname   
-----------+---------------+------------
 musicdb1  |         16389 | music_tbs
 musicdb2  |         16389 | music_tbs
 musicdb3  |         16389 | music_tbs
 musicdb   |         16389 | music_tbs
 postgres  |          1663 | pg_default
 omm       |          1663 | pg_default
 template0 |          1663 | pg_default
 template1 |          1663 | pg_default
(8 rows)

3.在文件系统中查看表空间中的多个数据库

--查看数据库、表空间的oid               

omm=#  select oid,datname from pg_database;
  oid  |  datname  
-------+-----------
     1 | template1
 16384 | omm
 16390 | musicdb
 14555 | template0
 16391 | musicdb1
 16392 | musicdb2
 16393 | musicdb3
 14560 | postgres
(8 rows)

omm=# select oid,* from pg_tablespace ;
  oid  |  spcname   | spcowner | spcacl | spcoptions | spcmaxsize | relative 
-------+------------+----------+--------+------------+------------+----------
  1663 | pg_default |       10 |        |            |            | f
  1664 | pg_global  |       10 |        |            |            | f
 16389 | music_tbs  |       10 |        |            |            | t
(3 rows)

omm=# select datname,dattablespace,spcname from pg_database d, pg_tablespace t where d.dattablespace=t.oid order by spcname; 
  datname  | dattablespace |  spcname   
-----------+---------------+------------
 musicdb1  |         16389 | music_tbs
 musicdb2  |         16389 | music_tbs
 musicdb3  |         16389 | music_tbs
 musicdb   |         16389 | music_tbs
 postgres  |          1663 | pg_default
 omm       |          1663 | pg_default
 template0 |          1663 | pg_default
 template1 |          1663 | pg_default
(8 rows)

--从文件系统，查看music_tbs表空间oid，可以看到一个表空间可以有多个数据库
 
/var/lib/opengauss/data/pg_tblspc/16389/PG_9.2_201611171_gaussdb
omm@modb:/var/lib/opengauss/data/pg_tblspc/16389/PG_9.2_201611171_gaussdb$ ls
16390  16391  16392  16393  pgsql_tmp

课后作业

1.创建表空间newtbs1

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

2.创建3个数据库newdb1、newdb2、newdb3，默认表空间为newtbs1

omm=# create database newdb1 with tablespace = newtbs1 ;
CREATE DATABASE
omm=# create database newdb2 with tablespace = newtbs1 ;
CREATE DATABASE
omm=# create database newdb3 with tablespace = newtbs1 ;
CREATE DATABASE

3.使用sql查看表空间newtbs1上有几个数据库

omm=# select oid,datname from pg_database;
  oid  |  datname  
-------+-----------
     1 | template1
 16384 | omm
 16390 | musicdb
 14555 | template0
 16391 | musicdb1
 16392 | musicdb2
 16393 | musicdb3
 14560 | postgres
 16399 | newdb1
 16400 | newdb2
 16401 | newdb3
(11 rows)
omm=# select oid,* from pg_tablespace ;
  oid  |  spcname   | spcowner | spcacl | spcoptions | spcmaxsize | relative 
-------+------------+----------+--------+------------+------------+----------
  1663 | pg_default |       10 |        |            |            | f
  1664 | pg_global  |       10 |        |            |            | f
 16389 | music_tbs  |       10 |        |            |            | t
 16398 | newtbs1    |       10 |        |            |            | t
(4 rows)
omm=# select datname,dattablespace,spcname from pg_database d, pg_tablespace t where d.dattablespace=t.oid order by spcname; 
  datname  | dattablespace |  spcname   
-----------+---------------+------------
 musicdb1  |         16389 | music_tbs
 musicdb3  |         16389 | music_tbs
 musicdb   |         16389 | music_tbs
 musicdb2  |         16389 | music_tbs
 newdb3    |         16398 | newtbs1
 newdb1    |         16398 | newtbs1
 newdb2    |         16398 | newtbs1
 postgres  |          1663 | pg_default
 template1 |          1663 | pg_default
 template0 |          1663 | pg_default
 omm       |          1663 | pg_default
(11 rows)

4.在文件系统中查看表空间newtbs1中的多个数据库
omm@modb:/var/lib/opengauss/data/pg_tblspc$ cd 16398
omm@modb:/var/lib/opengauss/data/pg_tblspc/16398$ ls
PG_9.2_201611171_gaussdb
omm@modb:/var/lib/opengauss/data/pg_tblspc/16398$ cd PG_9.2_201611171_gaussdb/
omm@modb:/var/lib/opengauss/data/pg_tblspc/16398/PG_9.2_201611171_gaussdb$ ls
16399  16400  16401  pgsql_tmp
omm@modb:/var/lib/opengauss/data/pg_tblspc/16398/PG_9.2_201611171_gaussdb$ ls -ltr
total 52
drwx------ 2 omm omm  4096 Dec  2 12:30 pgsql_tmp
drwx------ 2 omm omm 16384 Dec  2 12:32 16399
drwx------ 2 omm omm 16384 Dec  2 12:32 16400
drwx------ 2 omm omm 16384 Dec  2 12:32 16401