第10天 | openGauss逻辑结构：表空间管理

接着昨天继续学习openGauss,今天是第10天了。今天学习内容是openGauss逻辑结构：表空间管理。
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/tablespace_1';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb1 WITH TABLESPACE = t_tbspace ;
CREATE DATABASE
omm=# CREATE USER test IDENTIFIED BY 'test@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# ALTER USER test SYSADMIN;
omm=# ALTER ROLE
omm=# create table  t1 (col varchar(100)) TABLESPACE t_tbspace ; 
CREATE TABLE

2、查看表空间t_tbspace的oid和大小

omm=# \db
             List of tablespaces
    Name    | Owner |        Location         
------------+-------+-------------------------
 pg_default | omm   | 
 pg_global  | omm   | 
 t_tbspace  | omm   | tablespace/tablespace_1

–查看系统有哪些表空间

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

–查看表空间大小

omm=# SELECT PG_TABLESPACE_SIZE('t_tbspace');
 pg_tablespace_size 
--------------------
           12754948
(1 row)

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-# omm-#  select * 
 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 | reltablespace | relowner 
------------------------------------------+---------+----------+----------------+---------------+----------
 streaming_gather_agg_index               | i       |        2 | 16 kB          |             0 |       10
 snapshot_id_key                          | 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_cont_query_lookupidxid_index   | i       |        1 | 8192 bytes     |             0 |       10
 streaming_cont_query_schema_change_index | 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_cont_query_id_index            | i       |        1 | 8192 bytes     |             0 |       10
 streaming_cont_query_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_matrelid_index      | i       |        1 | 8192 bytes     |             0 |       10
 plan_table_data                          | 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
--More-- statement_history                        | r       |        0 | 0 bytes        |             0 |       10

4、查看数据库在非默认表空间下有哪些对象

–执行下面的SQL语句，查询数据库studentdb的非默认表空间t_tbspace下有哪些对象：

omm=#  select relname,relkind,relpages,pg_size_pretty(pg_relation_size(a.oid)),
omm-#           reltablespace,relowner
omm-#    from pg_class a, pg_tablespace tb
omm-# omm-#    where a.relkind in ('r', 'i')
   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 |       10
(1 row)

5、重命名表空间

–命名表空间t_tbspace为app_tbs

omm=# ALTER TABLESPACE t_tbspace RENAME TO app_tbs;
ALTER TABLESPACE

查看变更后表空间名称

omm=# \db
 pg_default | omm   | 
 pg_global  | omm   | 
(3 rows)

omm=#              List of tablespaces
    Name    | Owner |        Location         
------------+-------+-------------------------
 app_tbs    | omm   | tablespace/tablespace_1

6、删除表空间

–用户必须是表空间的owner或者系统管理员才能删除表空间。需要先删除表空间的对象，再删除表空间app_ts：

omm=# drop table t1;
DROP TABLE
omm=# DROP TABLESPACE app_tbs;
ERROR:  tablespace "app_tbs" is not empty
omm=# drop database musicdb1 ;
DROP DATABASE
omm=# DROP TABLESPACE app_tbs;
DROP TABLESPACE