ALTER SESSION

Function

ALTER SESSION defines or modifies the conditions or parameters that affect the current session. Modified session parameters are kept until the current session is disconnected.

Precautions

• If the START TRANSACTION statement is not executed before the SET TRANSACTION statement, the transaction is ended instantly and the statement does not take effect.
• You can use the transaction_mode(s) method declared in the START TRANSACTION statement to avoid using the SET TRANSACTION statement.

Syntax

• Set transaction parameters of a session.

  AlterSession ::= ALTER SESSION SET [ SESSION CHARACTERISTICS AS ] TRANSACTION
      { ISOLATION LEVEL { READ COMMITTED } | { READ ONLY  | READ WRITE } } [, ...] ;

• Set other running parameters of a session.

  AlterSession ::= ALTER SESSION SET
      {{config_parameter { { TO  | =  }  { value | DEFAULT }
        | FROM CURRENT }}
        | TIME ZONE time_zone
        | CURRENT_SCHEMA schema
        | NAMES encoding_name
        | ROLE role_name PASSWORD 'password'
        | SESSION AUTHORIZATION { role_name PASSWORD 'password' | DEFAULT }
        | XML OPTION { DOCUMENT | CONTENT }
      } ;

Parameter Description

For details about the descriptions of parameters related to ALTER SESSION, see Parameter Description of the SET syntax.

Examples

-- Create the ds schema.
mogdb=# CREATE SCHEMA ds;

-- Set the search path of the schema.
mogdb=# SET SEARCH_PATH TO ds, public;

-- Set the time/date type to the traditional postgres format (date before month).
mogdb=# SET DATESTYLE TO mogdb, dmy;

-- Set the character code of the current session to UTF8.
mogdb=# ALTER SESSION SET NAMES 'UTF8';

-- Set the time zone to Berkeley of California.
mogdb=# SET TIME ZONE 'PST8PDT';

-- Set the time zone to Italy.
mogdb=# SET TIME ZONE 'Europe/Rome';

-- Set the current schema.
mogdb=# ALTER SESSION SET CURRENT_SCHEMA TO tpcds;

-- Set XML OPTION to DOCUMENT.
mogdb=# ALTER SESSION SET XML OPTION DOCUMENT;

-- Create the role joe, and set the session role to joe.
mogdb=# CREATE ROLE joe WITH PASSWORD 'xxxxxxxxx';
mogdb=# ALTER SESSION SET SESSION AUTHORIZATION joe PASSWORD 'xxxxxxxxx';

-- Switch to the default user.
mogdb=> ALTER SESSION SET SESSION AUTHORIZATION default;

-- Delete the ds schema.
mogdb=# DROP SCHEMA ds;

-- Delete the role joe.
mogdb=# DROP ROLE joe;

Helpful Links

SET