Per http://www.postgresql.org/message-id/flat/
564C4CE6.
9000509@postgrespro.ru
Pavel Luzanov <p.luzanov@postgrespro.ru>
<para>
Specifies a libpq connection string to connect to the source
<productname>PostgreSQL</> server to synchronize the target with.
- The server must be up and running, and must not be in recovery mode.
+ The connection must be a normal (non-replication) connection
+ with superuser access. The server must be up and running,
+ and must not be in recovery mode.
</para>
</listitem>
</varlistentry>