2019独角兽企业重金招聘Python工程师标准>>> 
表空间作为数据库对象存放的地方,对于数据库来说是个逻辑概念,它是文件系统中一个目录下的多个数据文件组成. 目录可以不存放在PGDATA下,但是是作为cluster的一个部分,如果备份需要一起备份.
#创建表空间 只能使用superuser来创建表空间
postgres=# create tablespace ts01 location '/var/lib/pgsql/tsdata';
ERROR: directory "/var/lib/pgsql/tsdata" does not exist
postgres=# \! mkdir -p /var/lib/pgsql/tsdata --目录需要自己创建
postgres=# create tablespace ts01 location '/var/lib/pgsql/tsdata';
CREATE TABLESPACE
postgres=# create tablespace ts02 owner hippo location '/var/lib/pgsql/tsdata'; --同一个目录只能对应一个表空间
ERROR: directory "/var/lib/pgsql/tsdata/PG_9.4_201409291" already in use as a tablespace
postgres=# \! mkdir /var/lib/pgsql/tsdata02
postgres=# create tablespace ts02 owner hippo location '/var/lib/pgsql/tsdata02'; --可以指定用户
CREATE TABLESPACE
两种方式查看
postgres=# select * from pg_tablespace;
spcname | spcowner | spcacl | spcoptions
------------+----------+--------+------------
pg_default | 10 | |
pg_global | 10 | |
ts01 | 10 | |
ts02 | 16384 | |
(4 rows)
postgres=# \db
List of tablespaces
Name | Owner | Location
------------+----------+-------------------------
pg_default | postgres |
pg_global | postgres |
ts01 | postgres | /var/lib/pgsql/tsdata
ts02 | hippo | /var/lib/pgsql/tsdata02
(4 rows)
#表空间使用
postgres=# \c database2 user2;
You are now connected to database "database2" as user "user2".
database2=> create table t1(id text);
CREATE TABLE
默认对ts01没有权限
database2=> create table t2(id text) tablespace ts01;
ERROR: permission denied for tablespace ts01
database2=> \c - postgres
You are now connected to database "database2" as user "postgres".
database2=# alter database database2 set tablespace ts01; --连接在上面不能进行更改
ERROR: cannot change the tablespace of the currently open database
database2=# \c postgres postgres
You are now connected to database "postgres" as user "postgres".
ts01成为database2默认表空间
postgres=# alter database database2 set tablespace ts01;
ALTER DATABASE
postgres=# \c database2 user2
You are now connected to database "database2" as user "user2".
database2=> create table t2(id text) tablespace ts01;
CREATE TABLE
授权表空间权限给某用户
postgres=# \c database2 user2;
You are now connected to database "database2" as user "user2".
database2=> create table t3(id text) tablespace ts02; --没有ts02权限
ERROR: permission denied for tablespace ts02
database2=> \c postgres postgres
You are now connected to database "postgres" as user "postgres".
postgres=# grant create on tablespace ts02 to user2; --授权
GRANT
postgres=# \c database2 user2;
You are now connected to database "database2" as user "user2".
database2=> create table t3(id text) tablespace ts02;
CREATE TABLE
#表空间对应与文件系统 PGDATA下的pg_tblspc目录下存放的是表空间的链接
[postgres@fnddb pg_tblspc]$ pwd
/var/lib/pgsql/data/pg_tblspc
[postgres@fnddb pg_tblspc]$ ll
total 0
lrwxrwxrwx. 1 postgres postgres 21 Feb 6 22:52 16423 -> /var/lib/pgsql/tsdata
lrwxrwxrwx. 1 postgres postgres 23 Feb 6 23:04 16425 -> /var/lib/pgsql/tsdata02
#初始化cluster时默认的表空间说明 database cluster初始化时,默认创建两个表空间
- pg_global --系统字典表都存这里
- pg_default --template0,template1默认表空间,因此通过create database 不带tablespace参数创建的数据库都使用此表空间
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