查看表空间的语法帮助

postgres=# \h create tablespace
Command:     CREATE TABLESPACE
Description: define a new tablespace
Syntax:
CREATE TABLESPACE tablespace_name[ OWNER { new_owner | CURRENT_USER | SESSION_USER } ]LOCATION 'directory'[ WITH ( tablespace_option = value [, ... ] ) ]

创建表空间

连接coordinator：

create tablespace tst_tbs location '/home/shboss/antdb/data/tablespace';

需要在集群涉及到的主机上都存在location指定的目录，否则报错：

postgres=# create tablespace tst_tbs location '/home/shboss/antdb/data/tablespace';
ERROR:  Fail to process utility query on remote node.
DETAIL:  ERROR:  directory "/home/shboss/antdb/data/tablespace" does not exist

在各个主机上创建目录：

remote_cmd  "mkdir -p /home/shboss/antdb/data/tablespace"

再次连接coordinator创建表空间：

postgres=# create tablespace tst_tbs location '/home/shboss/antdb/data/tablespace';
CREATE TABLESPACE

查看表空间信息

数据库级别：

postgres=# \dbList of tablespacesName    | Owner  |              Location
------------+--------+------------------------------------pg_default | shboss | pg_global  | shboss | tst_tbs    | shboss | /home/shboss/antdb/data/tablespace
(3 rows)postgres=# select * from pg_tablespace ;spcname   | spcowner | spcacl | spcoptions
------------+----------+--------+------------pg_default |       10 |        | pg_global  |       10 |        | tst_tbs    |       10 |        |
(3 rows)

文件系统：

coord节点：

[shboss@localhost1 pg_tblspc]$ pwd
/home/shboss/antdb/data/coord/pg_tblspc

datanode 节点：

lrwxrwxrwx 1 shboss shboss 34 Jul 23 15:25 164514 -> /home/shboss/antdb/data/tablespace
[shboss@localhost1 pg_tblspc]$ pwd
/home/shboss/antdb/data/db1/pg_tblspc

表空间路径：

[shboss@localhost1 pg_tblspc]$ cd /home/shboss/antdb/data/tablespace
[shboss@localhost1 tablespace]$ ll
total 12
drwx------ 2 shboss shboss 4096 Jul 23 15:25 PG_9.6_201608131_coord1
drwx------ 2 shboss shboss 4096 Jul 23 15:25 PG_9.6_201608131_coord5
drwx------ 2 shboss shboss 4096 Jul 23 15:25 PG_9.6_201608131_db1_2
[shboss@localhost1 tablespace]$ tree .
.
├── PG_9.6_201608131_coord1
├── PG_9.6_201608131_coord5
└── PG_9.6_201608131_db1_2

在表空间内建表

create table test_tbs (id int) tablespace tst_tbs;

查看表空间中的数据文件：

[shboss@localhost1 tablespace]$ tree .
.
├── PG_9.6_201608131_coord1
│   └── 13603
│       └── 476507
├── PG_9.6_201608131_coord5
│   └── 13603
│       └── 18025
└── PG_9.6_201608131_db1_2└── 13597└── 164515

使用其他普通用户在tst_tbs 表空间下创建表：

bmsql5=> create table test_tbs (id int) tablespace tst_tbs;
ERROR:  permission denied for tablespace tst_tbs
bmsql5=>

解决办法1：给普通用户赋权

postgres=# grant create on tablespace tst_tbs to bmsql5_ora_fdw;
GRANT

再次建表成功：

bmsql5=> create table test_tbs (id int) tablespace tst_tbs;
CREATE TABLE
bmsql5=> \d+ test_tbsTable "bmsql5_ora_fdw.test_tbs"Column |  Type   | Modifiers | Storage | Stats target | Description
--------+---------+-----------+---------+--------------+-------------id     | integer |           | plain   |              |
Tablespace: "tst_tbs"
Distribute By: HASH(id)
Location Nodes: ALL DATANODESbmsql5=>

在创建之前，可以查询当前用户表空间tst_tbs 是否有权限：

bmsql5=> select has_tablespace_privilege('tst_tbs','create');has_tablespace_privilege
--------------------------t
(1 row)

revoke权限后再次查询：

-- superuser
postgres=# revoke create on tablespace tst_tbs from bmsql5_ora_fdw;
REVOKE
-- 普通用户
bmsql5=> select has_tablespace_privilege('tst_tbs','create');has_tablespace_privilege
--------------------------f
(1 row)

解决办法2：修改表空间的属主为表的创建用户

alter tablespace tst_tbs owner to bmsql5_ora_fdw;

再次建表成功：

bmsql5=> create table test_tbs (id int) tablespace tst_tbs;
CREATE TABLE
bmsql5=>

解决办法3：修改数据库的默认表空间

alter database bmsql5 set tablespace tst_tbs;postgres=# alter database bmsql5 set tablespace tst_tbs;
ALTER DATABASE
Time: 323772.143 ms
postgres=#
postgres=# \l+ List of databasesName    | Owner  | Encoding | Collate | Ctype | Access privileges |  Size   | Tablespace |                Description
-----------+--------+----------+---------+-------+-------------------+---------+------------+--------------------------------------------bmsql5    | shboss | UTF8     | C       | C     |                   | 26 GB   | tst_tbs    | db1       | shboss | UTF8     | C       | C     |                   | 1529 MB | pg_default | postgres  | shboss | UTF8     | C       | C     |                   | 43 MB   | pg_default | default administrative connection databasetemplate0 | shboss | UTF8     | C       | C     | =c/shboss        +| 30 MB   | pg_default | unmodifiable empty database|        |          |         |       | shboss=CTc/shboss |         |            | template1 | shboss | UTF8     | C       | C     | =c/shboss        +| 30 MB   | pg_default | default template for new databases|        |          |         |       | shboss=CTc/shboss |         |            | testdb    | shboss | UTF8     | C       | C     |                   | 108 MB  | pg_default |
(6 rows)

这个操作的耗时取决于数据库的大小和磁盘的性能。且在数据文件移动过程中，该数据库无法连接。

[shboss@localhost1 tablespace]$ psql -d bmsql5
psql: FATAL:  database "bmsql5" does not exist
DETAIL:  It seems to have just been dropped or renamed.

再次建表成功：

bmsql5=> create table test_tbs (id int) tablespace tst_tbs;
CREATE TABLE
bmsql5=> drop table test_tbs;
DROP TABLE
bmsql5=> create table test_tbs (id int);
CREATE TABLE

碰到的问题：

更改的数据库上有连接的时候，没法修改：

postgres=# alter database bmsql5 set tablespace tst_tbs;
ERROR:  database "bmsql5" is being accessed by other users
DETAIL:  There is 1 other session using the database.

连接到修改的数据库上也无法执行修改操作：

bmsql5=# alter database bmsql5 set tablespace tst_tbs;
ERROR:  cannot change the tablespace of the currently open database

如果修改的数据库中已经有对象在目标表空间中，也无法执行操作：

postgres=# alter database bmsql5 set tablespace tst_tbs;
ERROR:  some relations of database "bmsql5" are already in tablespace "tst_tbs"
HINT:  You must move them back to the database's default tablespace before using this command.

查找指定表空间中的对象：

select relname,reltype,spcname
from pg_class c, pg_tablespace tbs
where c.reltablespace=tbs.oid
and tbs.spcname='tst_tbs';

查看表的表空间

postgres=# \d test_tbsTable "public.test_tbs"Column |  Type   | Modifiers
--------+---------+-----------id     | integer |
Tablespace: "tst_tbs"

如果表没有使用所在数据库的默认表空间，则会在\d 的时候显示。

修改表的表空间

bmsql5=# select pg_relation_filepath('bmsql_stock');pg_relation_filepath
----------------------base/27636/461935
(1 row)bmsql5=# alter table bmsql_stock set tablespace tst_tbs;
ALTER TABLE
bmsql5=# select pg_relation_filepath('bmsql_stock');pg_relation_filepath
-------------------------------------------------------pg_tblspc/476505/PG_9.6_201608131_coord1/27636/476515
(1 row)bmsql5=#

表很大的话，会比较耗时，是个挪动文件的过程，同时发现filenode是变了的。

查看表空间大小

postgres=# select pg_tablespace_size('tst_tbs');pg_tablespace_size
--------------------36757504
(1 row)postgres=# select pg_size_pretty(pg_tablespace_size('tst_tbs'));pg_size_pretty
----------------35 MB
(1 row)

删除表空间

postgres=# drop tablespace tst_tbs;
ERROR:  tablespace "tst_tbs" is not empty

如果表空间中有对象删除，则无法删除。

根据上面提供的查找指定表空间中的对象 语句找出对象移走或删除后，再进行删除：

postgres=# drop tablespace tst_tbs;
DROP TABLESPACE

查看主机上的文件：

[shboss@localhost1 tablespace]$ tree .
.0 directories, 0 files
[shboss@localhost1 tablespace]$ pwd
/home/shboss/antdb/data/tablespace

目录已经为空。