password to be supplied from the server
    environment, such as a <filename>~/.pgpass</filename> file belonging to the
    server's user.  This opens not only a risk of impersonation, but the
    possibility of exposing a password to an untrustworthy remote server.
    Therefore, <function>dblink_connect_u()</function> is initially
    installed with all privileges revoked from <literal>PUBLIC</literal>,
    making it un-callable except by superusers.  In some situations
    it may be appropriate to grant <literal>EXECUTE</literal> permission for
    <function>dblink_connect_u()</function> to specific users who are considered
    trustworthy, but this should be done with care.  It is also recommended
    that any <filename>~/.pgpass</filename> file belonging to the server's user
    <emphasis>not</emphasis> contain any records specifying a wildcard host name.
   </para>

   <para>
    For further details see <function>dblink_connect()</function>.
   </para>
  </refsect1>
 </refentry>

 <refentry id="contrib-dblink-disconnect">
  <indexterm>
   <primary>dblink_disconnect</primary>
  </indexterm>

  <refmeta>
   <refentrytitle>dblink_disconnect</refentrytitle>
   <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
   <refname>dblink_disconnect</refname>
   <refpurpose>closes a persistent connection to a remote database</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
<synopsis>
dblink_disconnect() returns text
dblink_disconnect(text connname) returns text
</synopsis>
  </refsynopsisdiv>

  <refsect1>
   <title>Description</title>

   <para>
    <function>dblink_disconnect()</function> closes a connection previously opened
    by <function>dblink_connect()</function>.  The form with no arguments closes
    an unnamed connection.
   </para>
  </refsect1>

  <refsect1>
   <title>Arguments</title>

   <variablelist>
    <varlistentry>
     <term><parameter>connname</parameter></term>
     <listitem>
      <para>
       The name of a named connection to be closed.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect1>

  <refsect1>
   <title>Return Value</title>

   <para>
    Returns status, which is always <literal>OK</literal> (since any error
    causes the function to throw an error instead of returning).
   </para>
  </refsect1>

  <refsect1>
   <title>Examples</title>

<screen>
SELECT dblink_disconnect();
 dblink_disconnect
-------------------
 OK
(1 row)

SELECT dblink_disconnect('myconn');
 dblink_disconnect
-------------------
 OK
(1 row)
</screen>
  </refsect1>
 </refentry>

 <refentry id="contrib-dblink-function">
  <indexterm>
   <primary>dblink</primary>
  </indexterm>

  <refmeta>
   <refentrytitle>dblink</refentrytitle>
   <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
   <refname>dblink</refname>
   <refpurpose>executes a query in a remote database</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
<synopsis>
dblink(text connname, text sql [, bool fail_on_error]) returns setof record
dblink(text connstr, text sql [, bool fail_on_error]) returns setof record
dblink(text sql [, bool fail_on_error]) returns setof record
</synopsis>
  </refsynopsisdiv>

  <refsect1>
   <title>Description</title>

   <para>
    <function>dblink</function> executes a query (usually a <command>SELECT</command>,
    but it can be any SQL statement that returns rows) in a remote database.
   </para>

   <para>
    When two <type>text</type> arguments are given, the first one is first
    looked up as a persistent connection's name; if found, the command
    is executed on that connection.  If not found, the first argument
    is treated as a connection info string as for <function>dblink_connect</function>,
    and the indicated connection is made just for the duration of this command.
   </para>
  </refsect1>

  <refsect1>
   <title>Arguments</title>

   <variablelist>
    <varlistentry>
     <term><parameter>connname</parameter></term>
     <listitem>
      <para>
       Name of the connection to use; omit