Defines a new tablespace.
CREATE TABLESPACE <tablespace_name>
[OWNER <user_name>]
LOCATION '<directory>'
[WITH (content<ID_1>='<directory>'[, content<ID_2>='<directory>' ... ] [, <tablespace_option = value [, ... ] ])]
CREATE TABLESPACE
registers and configures a new tablespace for your Greenplum Database system. The tablespace name must be distinct from the name of any existing tablespace in the system. A tablespace is a Greenplum Database system object (a global object), you can use a tablespace from any database if you have appropriate privileges.
A tablespace allows superusers to define an alternative host file system location where the data files containing database objects (such as tables and indexes) reside.
A user with appropriate privileges can pass a tablespace name to CREATE DATABASE, CREATE TABLE, or CREATE INDEX to have the data files for these objects stored within the specified tablespace.
In Greenplum Database, the file system location must exist on all hosts including the hosts running the master, standby mirror, each primary segment, and each mirror segment.
pg_
or
gp_
, as such names are reserved for system tablespaces.
The absolute path to the directory (host system file location) that will be the root directory for the tablespace. When registering a tablepace, the directory should be empty and must be owned by the Greenplum Database system user. The directory must be specified by an absolute path name of no more than 100 characters. (The location is used to create a symlink target in the pg_tblspc directory, and symlink targets are truncated to 100 characters when sending to tar
from utilities such as pg_basebackup
.)
WITH
clause.
The value ID_i is the content ID for the segment instance. directory_i is the absolute path to the host system file location that the segment instance uses as the root directory for the tablespace. You cannot specify the content ID of the master instance (-1
). You can specify the same directory for multiple segments.
If a segment instance is not listed in the WITH
clause, Greenplum Database uses the tablespace directory specified in the LOCATION
clause.
LOCATION
directory also hold for directory_i.
Because CREATE TABLESPACE
creates symbolic links from the pg_tblspc
directory in the master and segment instance data directory to the directories specified in the command, Greenplum Database supports tablespaces only on systems that support symbolic links.
CREATE TABLESPACE
cannot be run inside a transaction block.
When creating tablespaces, ensure that file system locations have sufficient I/O speed and available disk space.
CREATE TABLESPACE
creates symbolic links from the pg_tblspc
directory in the master and segment instance data directory to the directories specified in the command.
The system catalog table pg_tablespace
stores tablespace information. This command displays the tablespace OID values, names, and owner.
SELECT oid, spcname, spcowner FROM pg_tablespace;
The Greenplum Database built-in function gp_tablespace_location(tablespace\_oid)
displays the tablespace host system file locations for all segment instances. This command lists the segment database IDs and host system file locations for the tablespace with OID 16385
.
SELECT * FROM gp_tablespace_location(16385)
NoteGreenplum Database does not support different tablespace locations for a primary-mirror pair with the same content ID. It is only possible to configure different locations for different content IDs. Do not modify symbolic links under the
pg_tblspc
directory so that primary-mirror pairs point to different file locations; this will lead to erroneous behavior.
Create a new tablespace and specify the file system location for the master and all segment instances:
CREATE TABLESPACE mytblspace LOCATION '/gpdbtspc/mytestspace';
Create a new tablespace and specify a location for segment instances with content ID 0 and 1. For the master and segment instances not listed in the WITH
clause, the file system location for the tablespace is specified in the LOCATION
clause.
CREATE TABLESPACE mytblspace LOCATION '/gpdbtspc/mytestspace' WITH (content0='/temp/mytest', content1='/temp/mytest');
The example specifies the same location for the two segment instances. You can a specify different location for each segment.
CREATE TABLESPACE
is a Greenplum Database extension.
CREATE DATABASE, CREATE TABLE, CREATE INDEX, DROP TABLESPACE, ALTER TABLESPACE
Parent topic: SQL Commands