CREATE TABLESPACE
CREATE TABLESPACE
CREATE TABLESPACE - define a new tablespace
Synopsis
CREATE TABLESPACEtablespace_name
[ OWNER {new_owner
| CURRENT_ROLE | CURRENT_USER | SESSION_USER } ] LOCATION 'directory
' [ WITH (tablespace_option
=value
[, ... ] ) ]
Description
CREATE TABLESPACE
registers a new cluster-wide
tablespace. The tablespace name must be distinct from the name of any
existing tablespace in the database cluster.
A tablespace allows superusers to define an alternative location on the file system where the data files containing database objects (such as tables and indexes) can reside.
A user with appropriate privileges can pass
tablespace_name
to
CREATE DATABASE
,
CREATE TABLE
,
CREATE INDEX
or
ADD CONSTRAINT
to have the data
files for these objects stored within the specified tablespace.
Warning
A tablespace cannot be used independently of the cluster in which it is defined; see Section 23.6 .
Parameters
-
tablespace_name
-
The name of a tablespace to be created. The name cannot begin with
pg_
, as such names are reserved for system tablespaces. -
user_name
-
The name of the user who will own the tablespace. If omitted, defaults to the user executing the command. Only superusers can create tablespaces, but they can assign ownership of tablespaces to non-superusers.
-
directory
-
The directory that will be used for the tablespace. The directory must exist (
CREATE TABLESPACE
will not create it), should be empty, and must be owned by the PostgreSQL system user. The directory must be specified by an absolute path name. -
tablespace_option
-
A tablespace parameter to be set or reset. Currently, the only available parameters are
seq_page_cost
,random_page_cost
,effective_io_concurrency
andmaintenance_io_concurrency
. Setting these values for a particular tablespace will override the planner's usual estimate of the cost of reading pages from tables in that tablespace, and the executor's prefetching behavior, as established by the configuration parameters of the same name (see seq_page_cost , random_page_cost , effective_io_concurrency , maintenance_io_concurrency ). This may be useful if one tablespace is located on a disk which is faster or slower than the remainder of the I/O subsystem.
Notes
Tablespaces are only supported on systems that support symbolic links.
CREATE TABLESPACE
cannot be executed inside a transaction
block.
Examples
To create a tablespace
dbspace
at file system location
/data/dbs
, first create the directory using operating
system facilities and set the correct ownership:
mkdir /data/dbs chown postgres:postgres /data/dbs
Then issue the tablespace creation command inside PostgreSQL :
CREATE TABLESPACE dbspace LOCATION '/data/dbs';
To create a tablespace owned by a different database user, use a command like this:
CREATE TABLESPACE indexspace OWNER genevieve LOCATION '/data/indexes';
Compatibility
CREATE TABLESPACE
is a
PostgreSQL
extension.