doc/src/sgml/ref/alter_role.sgml - master - githubmirror/postgres

doc/src/sgml/ref/alter_role.sgml
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Nathan Bossart
Improve some documentation about the bootstrap superuser.
19 янв 2024, 06:39
19 янв 2024, 06:39d891dcc
<!--
doc/src/sgml/ref/alter_role.sgml
PostgreSQL documentation
-->

<refentry id="sql-alterrole">
 <indexterm zone="sql-alterrole">
  <primary>ALTER ROLE</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>ALTER ROLE</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER ROLE</refname>
  <refpurpose>change a database role</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ALTER ROLE <replaceable class="parameter">role_specification</replaceable> [ WITH ] <replaceable class="parameter">option</replaceable> [ ... ]

<phrase>where <replaceable class="parameter">option</replaceable> can be:</phrase>

      SUPERUSER | NOSUPERUSER
    | CREATEDB | NOCREATEDB
    | CREATEROLE | NOCREATEROLE
    | INHERIT | NOINHERIT
    | LOGIN | NOLOGIN
    | REPLICATION | NOREPLICATION
    | BYPASSRLS | NOBYPASSRLS
    | CONNECTION LIMIT <replaceable class="parameter">connlimit</replaceable>
    | [ ENCRYPTED ] PASSWORD '<replaceable class="parameter">password</replaceable>' | PASSWORD NULL
    | VALID UNTIL '<replaceable class="parameter">timestamp</replaceable>'

ALTER ROLE <replaceable class="parameter">name</replaceable> RENAME TO <replaceable>new_name</replaceable>

ALTER ROLE { <replaceable class="parameter">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="parameter">database_name</replaceable> ] SET <replaceable>configuration_parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
ALTER ROLE { <replaceable class="parameter">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="parameter">database_name</replaceable> ] SET <replaceable>configuration_parameter</replaceable> FROM CURRENT
ALTER ROLE { <replaceable class="parameter">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="parameter">database_name</replaceable> ] RESET <replaceable>configuration_parameter</replaceable>
ALTER ROLE { <replaceable class="parameter">role_specification</replaceable> | ALL } [ IN DATABASE <replaceable class="parameter">database_name</replaceable> ] RESET ALL

<phrase>where <replaceable class="parameter">role_specification</replaceable> can be:</phrase>

    <replaceable class="parameter">role_name</replaceable>
  | CURRENT_ROLE
  | CURRENT_USER
  | SESSION_USER
</synopsis>
 </refsynopsisdiv>

 <refsect1 id="sql-alterrole-desc">
  <title>Description</title>

  <para>
   <command>ALTER ROLE</command> changes the attributes of a
   <productname>PostgreSQL</productname> role.
  </para>

  <para>
   The first variant of this command listed in the synopsis can change
   many of the role attributes that can be specified in
   <link linkend="sql-createrole"><command>CREATE ROLE</command></link>.
   (All the possible attributes are covered,
   except that there are no options for adding or removing memberships; use
   <link linkend="sql-grant"><command>GRANT</command></link> and
   <link linkend="sql-revoke"><command>REVOKE</command></link> for that.)
   Attributes not mentioned in the command retain their previous settings.
   Database superusers can change any of these settings for any role, except
   for changing the <literal>SUPERUSER</literal> property for the
   <glossterm linkend="glossary-bootstrap-superuser">bootstrap superuser</glossterm>.
   Non-superuser roles having <literal>CREATEROLE</literal> privilege can
   change most of these properties, but only for non-superuser and
   non-replication roles for which they have been granted
   <literal>ADMIN OPTION</literal>. Non-superusers cannot change the
   <literal>SUPERUSER</literal> property and can change the
   <literal>CREATEDB</literal>, <literal>REPLICATION</literal>, and
   <literal>BYPASSRLS</literal> properties only if they possess the
   corresponding property themselves.
   Ordinary roles can only change their own password.
  </para>

  <para>
   The second variant changes the name of the role.
   Database superusers can rename any role.
   Roles having <literal>CREATEROLE</literal> privilege can rename non-superuser
   roles for which they have been granted <literal>ADMIN OPTION</literal>.
   The current session user cannot be renamed.
   (Connect as a different user if you need to do that.)
   Because <literal>MD5</literal>-encrypted passwords use the role name as
   cryptographic salt, renaming a role clears its password if the
   password is <literal>MD5</literal>-encrypted.
  </para>

  <para>
   The remaining variants change a role's session default for a configuration
   variable, either for all databases or, when the <literal>IN
   DATABASE</literal> clause is specified, only for sessions in the named
   database.  If <literal>ALL</literal> is specified instead of a role name,
   this changes the setting for all roles.  Using <literal>ALL</literal>
   with <literal>IN DATABASE</literal> is effectively the same as using the
   command <literal>ALTER DATABASE ... SET ...</literal>.
  </para>

  <para>
   Whenever the role subsequently
   starts a new session, the specified value becomes the session
   default, overriding whatever setting is present in
   <filename>postgresql.conf</filename> or has been received from the <command>postgres</command>
   command line. This only happens at login time; executing
   <link linkend="sql-set-role"><command>SET ROLE</command></link> or
   <link linkend="sql-set-session-authorization"><command>SET SESSION AUTHORIZATION</command></link> does not cause new
   configuration values to be set.
   Settings set for all databases are overridden by database-specific settings
   attached to a role.  Settings for specific databases or specific roles override
   settings for all roles.
  </para>

  <para>
   Superusers can change anyone's session defaults. Roles having
   <literal>CREATEROLE</literal> privilege can change defaults for non-superuser
   roles for which they have been granted <literal>ADMIN OPTION</literal>.
   Ordinary roles can only set defaults for themselves.
   Certain configuration variables cannot be set this way, or can only be
   set if a superuser issues the command.  Only superusers can change a setting
   for all roles in all databases.
  </para>
 </refsect1>

 <refsect1 id="sql-alterrole-params">
  <title>Parameters</title>

    <variablelist>
     <varlistentry id="sql-alterrole-params-name">
      <term><replaceable class="parameter">name</replaceable></term>
      <listitem>
       <para>
        The name of the role whose attributes are to be altered.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="sql-alterrole-params-current-role">
      <term><literal>CURRENT_ROLE</literal></term>
      <term><literal>CURRENT_USER</literal></term>
      <listitem>
       <para>
        Alter the current user instead of an explicitly identified role.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="sql-alterrole-params-session-user">
      <term><literal>SESSION_USER</literal></term>
      <listitem>
       <para>
        Alter the current session user instead of an explicitly identified
        role.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="sql-alterrole-params-superuser">
      <term><literal>SUPERUSER</literal></term>
      <term><literal>NOSUPERUSER</literal></term>
      <term><literal>CREATEDB</literal></term>
      <term><literal>NOCREATEDB</literal></term>
      <term><literal>CREATEROLE</literal></term>
      <term><literal>NOCREATEROLE</literal></term>
      <term><literal>INHERIT</literal></term>
      <term><literal>NOINHERIT</literal></term>
      <term><literal>LOGIN</literal></term>
      <term><literal>NOLOGIN</literal></term>
      <term><literal>REPLICATION</literal></term>
      <term><literal>NOREPLICATION</literal></term>
      <term><literal>BYPASSRLS</literal></term>
      <term><literal>NOBYPASSRLS</literal></term>
      <term><literal>CONNECTION LIMIT</literal> <replaceable class="parameter">connlimit</replaceable></term>
      <term>[ <literal>ENCRYPTED</literal> ] <literal>PASSWORD</literal> '<replaceable class="parameter">password</replaceable>'</term>
      <term><literal>PASSWORD NULL</literal></term>
      <term><literal>VALID UNTIL</literal> '<replaceable class="parameter">timestamp</replaceable>'</term>
      <listitem>
       <para>
        These clauses alter attributes originally set by
        <link linkend="sql-createrole"><command>CREATE ROLE</command></link>. For more information, see the
        <command>CREATE ROLE</command> reference page.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="sql-alterrole-params-new-name">
      <term><replaceable>new_name</replaceable></term>
      <listitem>
       <para>
        The new name of the role.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="sql-alterrole-params-database-name">
       <term><replaceable>database_name</replaceable></term>
       <listitem>
         <para>
           The name of the database the configuration variable should be set in.
         </para>
       </listitem>
     </varlistentry>

     <varlistentry id="sql-alterrole-params-configuration-parameter">
      <term><replaceable>configuration_parameter</replaceable></term>
      <term><replaceable>value</replaceable></term>
      <listitem>
       <para>
        Set this role's session default for the specified configuration
        parameter to the given value.  If
        <replaceable>value</replaceable> is <literal>DEFAULT</literal>
        or, equivalently, <literal>RESET</literal> is used, the
        role-specific variable setting is removed, so the role will
        inherit the system-wide default setting in new sessions.  Use
        <literal>RESET ALL</literal> to clear all role-specific settings.
        <literal>SET FROM CURRENT</literal> saves the session's current value of
        the parameter as the role-specific value.
        If <literal>IN DATABASE</literal> is specified, the configuration
        parameter is set or removed for the given role and database only.
       </para>

       <para>
        Role-specific variable settings take effect only at login;
        <link linkend="sql-set-role"><command>SET ROLE</command></link> and
        <link linkend="sql-set-session-authorization"><command>SET SESSION AUTHORIZATION</command></link>
        do not process role-specific variable settings.
       </para>

       <para>
        See <xref linkend="sql-set"/> and <xref
        linkend="runtime-config"/> for more information about allowed
        parameter names and values.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
 </refsect1>

 <refsect1 id="sql-alterrole-notes">
  <title>Notes</title>

  <para>
   Use <link linkend="sql-createrole"><command>CREATE ROLE</command></link>
   to add new roles, and <link linkend="sql-droprole"><command>DROP ROLE</command></link> to remove a role.
  </para>

  <para>
   <command>ALTER ROLE</command> cannot change a role's memberships.
   Use <link linkend="sql-grant"><command>GRANT</command></link> and
   <link linkend="sql-revoke"><command>REVOKE</command></link>
   to do that.
  </para>

  <para>
   Caution must be exercised when specifying an unencrypted password
   with this command.  The password will be transmitted to the server
   in cleartext, and it might also be logged in the client's command
   history or the server log.  <xref linkend="app-psql"/>
   contains a command
   <command>\password</command> that can be used to change a
   role's password without exposing the cleartext password.
  </para>

  <para>
   It is also possible to tie a
   session default to a specific database rather than to a role; see
   <xref linkend="sql-alterdatabase"/>.
   If there is a conflict, database-role-specific settings override role-specific
   ones, which in turn override database-specific ones.
  </para>
 </refsect1>

 <refsect1 id="sql-alterrole-examples">
  <title>Examples</title>

  <para>
   Change a role's password:

<programlisting>
ALTER ROLE davide WITH PASSWORD 'hu8jmn3';
</programlisting>
  </para>

  <para>
   Remove a role's password:

<programlisting>
ALTER ROLE davide WITH PASSWORD NULL;
</programlisting>
  </para>

  <para>
   Change a password expiration date, specifying that the password
   should expire at midday on 4th May 2015 using
   the time zone which is one hour ahead of <acronym>UTC</acronym>:
<programlisting>
ALTER ROLE chris VALID UNTIL 'May 4 12:00:00 2015 +1';
</programlisting>
  </para>

  <para>
   Make a password valid forever:
<programlisting>
ALTER ROLE fred VALID UNTIL 'infinity';
</programlisting>
  </para>

  <para>
   Give a role the ability to manage other roles and create new databases:

<programlisting>
ALTER ROLE miriam CREATEROLE CREATEDB;
</programlisting>
  </para>

  <para>
   Give a role a non-default setting of the
   <xref linkend="guc-maintenance-work-mem"/> parameter:

<programlisting>
ALTER ROLE worker_bee SET maintenance_work_mem = 100000;
</programlisting>
  </para>

  <para>
   Give a role a non-default, database-specific setting of the
   <xref linkend="guc-client-min-messages"/> parameter:

<programlisting>
ALTER ROLE fred IN DATABASE devel SET client_min_messages = DEBUG;
</programlisting></para>
 </refsect1>

 <refsect1 id="sql-alterrole-compat">
  <title>Compatibility</title>

  <para>
   The <command>ALTER ROLE</command> statement is a
   <productname>PostgreSQL</productname> extension.
  </para>
 </refsect1>

 <refsect1 id="sql-alterrole-see">
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-createrole"/></member>
   <member><xref linkend="sql-droprole"/></member>
   <member><xref linkend="sql-alterdatabase"/></member>
   <member><xref linkend="sql-set"/></member>
  </simplelist>
 </refsect1>
</refentry>