postgres 表空間創建和查詢

--//創建表空間所需目錄
[postgres@postgres ~]$ mkdir tbs
[postgres@postgres ~]$ pwd
/home/postgres
[postgres@postgres ~]$ cd pg11
[postgres@postgres pg11]$ p
psql (11.1)

--//創建表空間語法
postgres=# \help 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 [, ... ] ) ]

postgres=# CREATE TABLESPACE tbs location '/home/postgres/tbs';
CREATE TABLESPACE
postgres=# 
postgres=# create table emp(id int) tablespace tbs;
CREATE TABLE
postgres=# 
postgres=# insert into emp values (10);
INSERT 0 1
postgres=# \df *filepath*
                                 List of functions
   Schema   |         Name         | Result data type | Argument data types | Type 
------------+----------------------+------------------+---------------------+------
 pg_catalog | pg_relation_filepath | text             | regclass            | func
(1 row)

postgres=# select pg_relation_filepath('emp');
            pg_relation_filepath             
---------------------------------------------
 pg_tblspc/16387/PG_11_201809051/13237/16388
(1 row)

--//pg_tblspc/16387/PG_11_201809051/13237/16388
--//其中pg_tblspc是表空間的目錄
[postgres@postgres pg11]$ cd pg_t
pg_tblspc/   pg_twophase/ 
[postgres@postgres pg11]$ cd pg_tblspc/
[postgres@postgres pg_tblspc]$ ls -ltr
total 0
lrwxrwxrwx 1 postgres postgres 18 Apr  1 10:25 16387 -> /home/postgres/tbs

--//16387代表表空間的oid
postgres=# select oid, spcname from pg_tablespace;
  oid  |  spcname   
-------+------------
  1663 | pg_default
  1664 | pg_global
 16387 | tbs
(3 rows)

postgres=# 

--//PG_11_201809051代表postgres的版本和
數據庫版本
[postgres@postgres pg11]$ pg_controldata 
pg_control version number:            1100
Catalog version number:               201809051     
Database system identifier:           6779218108159293483
Database cluster state:               in production
pg_control last modified:             Wed 01 Apr 2020 10:28:43 AM EDT
Latest checkpoint location:           0/4015138
Latest checkpoint's REDO location:    0/4015100
Latest checkpoint's REDO WAL file:    000000010000000000000004

--//13237代表數據庫的oid
postgres=# select oid, datname from pg_database;
  oid  |  datname  
-------+-----------
 13237 | postgres
     1 | template1
 13236 | template0
(3 rows)

postgres=# 

--//16388代表emp對象的oid

postgres=# \df *filenode*
                                 List of functions
   Schema   |         Name         | Result data type | Argument data types | Type 
------------+----------------------+------------------+---------------------+------
 pg_catalog | pg_filenode_relation | regclass         | oid, oid            | func
 pg_catalog | pg_relation_filenode | oid              | regclass            | func
(2 rows)

postgres=# select pg_relation_filenode('emp');
 pg_relation_filenode 
----------------------
                16388
(1 row)

postgres=# 
postgres=# select oid, relname from pg_class where relname = 'emp';
  oid  | relname 
-------+---------
 16388 | emp
(1 row)

postgres=# 

postgres=# \db
            List of tablespaces
    Name    |  Owner   |      Location      
------------+----------+--------------------
 pg_default | postgres | 
 pg_global  | postgres | 
 tbs        | postgres | /home/postgres/tbs
(3 rows)

postgres=# 
postgres=#