CREATE TABLESPACE — define a new tablespace
CREATE TABLESPACEtablespace_name[ OWNER {new_owner| CURRENT_ROLE | CURRENT_USER | SESSION_USER } ] LOCATION 'directory' [ WITH (tablespace_option=value[, ... ] ) ]
   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.
  
A tablespace cannot be used independently of the cluster in which it is defined; see Section 22.6.
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_nameThe 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
        and maintenance_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.
       
    CREATE TABLESPACE cannot be executed inside a transaction
    block.
   
   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';
   CREATE TABLESPACE is a PostgreSQL
   extension.