利用tablespace特性将数据库移动到新磁盘

目前开发一台EC2的PostgreSQL服务器的磁盘空间已经严重不足，该磁盘非LVM，所以不考虑磁盘扩容方法，研发希望可以分区/data/02对应的/dev/xvdl1磁盘分担部分数据库的数据，这样也不用另加磁盘，这里研发列出了部分数据库。此处借用tablespace特性将部分数据迁移到新磁盘

[postgres@ec2s-autodenalicontentpoi- ~]$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvde1            .9G  .3G  .2G  % /
none                   15G   12K   15G   % /dev/shm
/dev/xvdl1            493G   46G  422G  % /data/
/dev/xvdk1            .0T  .8T  113G  % /data/
hq-nfs-.eng.telenav.com:/nfs_home/home/
                      985G   22G  964G   % /nfs/home

查看当前所有数据库大小

postgres=# \l+
                                                                             List of databases
        Name        |    Owner    | Encoding |   Collate   |    Ctype    |      Access privileges       |  Size  | Tablespace |                Description
--------------------+-------------+----------+-------------+-------------+------------------------------+--------+------------+--------------------------------------------
 contrib_regression | postgres    | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 15 MB  | pg_default |
 denali             | postgres    | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =Tc/postgres                +| 357 MB | pg_default |
                    |             |          |             |             | postgres=CTc/postgres       +|        |            |
                    |             |          |             |             | r_denali_readonly=c/postgres |        |            |
 denali_test        | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 15 MB  | pg_default |
 fuse               | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 15 MB  | pg_default |
 postgres           | postgres    | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 27 MB  | pg_default | default administrative connection database
 region_anz         | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 17 GB  | pg_default |
 region_eu          | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 447 GB | pg_default |
 region_il          | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 12 GB  | pg_default |
 region_mea         | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 69 GB  | pg_default |
 region_na          | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 603 GB | pg_default |
 region_sa          | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 188 GB | pg_default |
 region_sea         | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 62 GB  | pg_default |
 regression         | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 91 GB  | pg_default |
 template0          | postgres    | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres                 +| 14 MB  | pg_default | unmodifiable empty database
                    |             |          |             |             | postgres=CTc/postgres        |        |            |
 template1          | postgres    | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres                 +| 14 MB  | pg_default | default template for new databases
                    |             |          |             |             | postgres=CTc/postgres        |        |            |
 template_postgis   | postgres    | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 19 MB  | pg_default |
 test               | denaliadmin | UTF8     | en_US.UTF-8 | en_US.UTF-8 |                              | 14 MB  | pg_default |
(17 rows)

创建新的表空间

[postgres@ec2s-autodenalicontentpoi-01]$ mkdir -p /data/02/pgsql/data/base

postgres=# create tablespace region owner denaliadmin location
'/data/02/pgsql/data/base';
postgres=# \db+
                                  List of tablespaces
    Name    |    Owner    |         Location         | Access privileges | Description
------------+-------------+--------------------------+-------------------+-------------
 pg_default | postgres    |                          |                   |
 pg_global  | postgres    |                          |                   |
 region     | denaliadmin | /data/02/pgsql/data/base |                   |
(3 rows)
postgres=# select oid, * from pg_database;
  oid   |      datname       | datdba | encoding | datcollate  |  datctype   | datistemplate | datallowconn | datconnlimit | datlastsysoid | datfrozenxid | datminmxid | dattablespace |                              datacl
--------+--------------------+--------+----------+-------------+-------------+---------------+--------------+--------------+---------------+--------------+------------+---------------+-------------------------------------------------------------------
      1 | template1          |     10 |        6 | en_US.UTF-8 | en_US.UTF-8 | t             | t            |           -1 |         12835 |    200001862 |          1 |          1663 | {=c/postgres,postgres=CTc/postgres}
  12835 | template0          |     10 |        6 | en_US.UTF-8 | en_US.UTF-8 | t             | f            |           -1 |         12835 |    200001940 |          1 |          1663 | {=c/postgres,postgres=CTc/postgres}
  12840 | postgres           |     10 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    295302735 |          1 |          1663 |
  16384 | template_postgis   |     10 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    205319808 |          1 |          1663 |
  21627 | denali_test        |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    205320018 |          1 |          1663 |
  17794 | denali             |     10 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    205316770 |          1 |          1663 | {=Tc/postgres,postgres=CTc/postgres,r_denali_readonly=c/postgres}
  25419 | contrib_regression |     10 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    295302735 |          1 |          1663 |
  71746 | regression         |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    187750513 |          1 |          1663 |
 103050 | test               |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    200001862 |          1 |          1663 |
  48729 | region_na          |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    190246393 |          1 |          1663 |
 153385 | region_sea         |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    200001862 |          1 |          1663 |
 158397 | fuse               |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    200001862 |          1 |          1663 |
  81870 | region_eu          |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    192495454 |          1 |          1663 |
  93796 | region_sa          |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    200778866 |          1 |          1663 |
  99928 | region_mea         |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    190246488 |          1 |          1663 |
 101209 | region_il          |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    199337179 |          1 |          1663 |
 101862 | region_anz         |  16513 |        6 | en_US.UTF-8 | en_US.UTF-8 | f             | t            |           -1 |         12835 |    199763417 |          1 |          1663 |
(17 rows)
postgres=# select oid,* from pg_tablespace;
  oid   |  spcname   | spcowner | spcacl | spcoptions
--------+------------+----------+--------+------------
   1663 | pg_default |       10 |        |
   1664 | pg_global  |       10 |        |
 271240 | region     |    16513 |        |
(3 rows)

将部分数据库迁移到新的表空间

postgres=# alter database region_il set tablespace region;
postgres=# alter database region_anz set tablespace region;
postgres=# alter database region_mea set tablespace region;
postgres=# alter database region_sa set tablespace region;

postgres=# select d.datname as database, t.spcname as tablespace from pg_database d, pg_tablespace t where d.dattablespace=t.oid;
      database      | tablespace
--------------------+------------
 template1          | pg_default
 template0          | pg_default
 postgres           | pg_default
 template_postgis   | pg_default
 denali_test        | pg_default
 denali             | pg_default
 contrib_regression | pg_default
 regression         | pg_default
 test               | pg_default
 region_na          | pg_default
 region_sea         | pg_default
 region_il          | region
 region_anz         | region
 region_mea         | region
 region_sa          | region
 fuse               | pg_default
 region_eu          | pg_default
(17 rows)