openGauss自带了两个表空间：pg_default和pg_global。

默认表空间pg_default：用来存储非共享系统表、用户表、用户表index、临时表、临时表index、内部临时表的默认表空间。对应存储目录为实例数据目录下的base目录。

共享表空间pg_global：用来存放共享系统表的表空间。对应存储目录为实例数据目录下的global目录。

作业

1、创建表空间t_tbspace、用户test，并使用test，在这个表空间上创建表t1

omm=# CREATE TABLESPACE t_tbspace RELATIVE LOCATION 'tablespace/t_tbspace1';
CREATE TABLESPACE
--查看系统有哪些表空间
omm=# \db
            List of tablespaces
    Name    | Owner |       Location        
------------+-------+-----------------------
 pg_default | omm   | 
 pg_global  | omm   | 
 t_tbspace  | omm   | tablespace/t_tbspace1
(3 rows)

omm=# CREATE USER test IDENTIFIED BY 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# GRANT CREATE ON TABLESPACE t_tbspace TO test ;
GRANT
omm=# \c - test
Password for user test: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "test".
omm=> CREATE TABLE t1(i int) TABLESPACE t_tbspace;
CREATE TABLE
omm=> 

2、查看表空间t_tbspace的oid和大小

omm=> SELECT PG_TABLESPACE_SIZE('t_tbspace');
 pg_tablespace_size 
--------------------
               8192
(1 row)

omm=> select oid,* from pg_tablespace ;
  oid  |  spcname   | spcowner |         spcacl         | spcoptions | spcmaxsize | rela
tive 
-------+------------+----------+------------------------+------------+------------+-----
-----
  1663 | pg_default |       10 |                        |            |            | f
  1664 | pg_global  |       10 |                        |            |            | f
 16389 | t_tbspace  |       10 | {omm=C/omm,test=C/omm} |            |            | t
(3 rows)

3、查看数据库在默认表空间下有哪些对象

omm=> with objectInDefaultTS as
omm->           ( select relname, relkind, relpages,pg_size_pretty(pg_relation_size(a.oid)),
omm(>                   reltablespace,relowner
omm(>             from pg_class a
omm(>             where a.relkind in ('r', 'i')  and reltablespace='0'
omm(>          )
omm->  select * 
omm->  from objectInDefaultTS 
omm->    where relname not like 'pg_%' and relname not like 'gs_%' and relname not like 'sql_%'
omm->  order by relpages desc;
                 relname                  | relkind | relpages | pg_size_pretty | reltab
lespace | relowner 
------------------------------------------+---------+----------+----------------+-------
--------+---------- streaming_gather_agg_index               | i       |        2 | 16 kB          |       
      0 |       10
 snapshot_id_key                          | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_cont_query_schema_change_index | i       |        1 | 8192 bytes     |       
      0 |       10

 streaming_cont_query_lookupidxid_index   | i       |        1 | 8192 bytes     |       
      0 |       10

 snapshot_pkey                            | i       |        1 | 8192 bytes     |       
      0 |       10
 statement_history_time_idx               | i       |        1 | 8192 bytes     |       
      0 |       10 streaming_reaper_status_id_index         | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_reaper_status_oid_index        | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_stream_oid_index               | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_stream_relid_index             | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_cont_query_relid_index         | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_cont_query_defrelid_index      | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_cont_query_id_index            | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_cont_query_oid_index           | i       |        1 | 8192 bytes     |       
      0 |       10
 streaming_cont_query_matrelid_index      | i       |        1 | 8192 bytes     |       
      0 |       10
 plan_table_data                          | r       |        0 | 0 bytes        |       
      0 |       10
 statement_history                        | r       |        0 | 0 bytes        |       
      0 |       10
 streaming_stream                         | r       |        0 | 0 bytes        |       
      0 |       10
 snapshot                                 | r       |        0 | 0 bytes        |       
      0 |       10
 streaming_reaper_status                  | r       |        0 | 0 bytes        |       
      0 |       10
 streaming_cont_query                     | r       |        0 | 0 bytes        |       
      0 |       10
(21 rows)--More--

4、查看数据库在非默认表空间下有哪些对象

omm-> select relname,relkind,relpages,pg_size_pretty(pg_relation_size(a.oid)),
reltablespace,relowner
omm-> from pg_class a, pg_tablespace tb
omm-> where a.relkind in (‘r’, ‘i’)
omm-> and a.reltablespace=tb.oid
omm-> and tb.spcname=‘t_tbspace’
omm-> order by a.relpages desc;
relname | relkind | relpages | pg_size_pretty | reltablespace | relowner
---------±--------±---------±---------------±--------------±---------
t1 | r | 0 | 0 bytes | 16389 | 16390
(1 row)

5、重命名表空间

omm=> \c - omm
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "omm".
omm=# 
omm=# 
omm=# 
omm=# ALTER TABLESPACE t_tbspace RENAME TO app_tbs;
ALTER TABLESPACE

6、删除表空间

omm=# drop table test.t1 ;
DROP TABLE
omm=# DROP TABLESPACE app_tbs;
DROP TABLESPACE