</para>

<para>Once running, the process can connect to a database by calling

<function>BackgroundWorkerInitializeConnection(<parameter>char *dbname</parameter>, <parameter>char *username</parameter>)</function> or

<function>BackgroundWorkerInitializeConnectionByOid(<parameter>Oid dboid</parameter>, <parameter>Oid useroid</parameter>)</function>.

<function>BackgroundWorkerInitializeConnection(<parameter>char *dbname</parameter>, <parameter>char *username</parameter>, <parameter>uint32 flags</parameter>)</function> or

<function>BackgroundWorkerInitializeConnectionByOid(<parameter>Oid dboid</parameter>, <parameter>Oid useroid</parameter>, <parameter>uint32 flags</parameter>)</function>.

This allows the process to run transactions and queries using the

<literal>SPI</literal> interface. If <varname>dbname</varname> is NULL or

<varname>dboid</varname> is <literal>InvalidOid</literal>, the session is not connected

to any particular database, but shared catalogs can be accessed.

If <varname>username</varname> is NULL or <varname>useroid</varname> is

<literal>InvalidOid</literal>, the process will run as the superuser created

during <command>initdb</command>.

during <command>initdb</command>. If <literal>BGWORKER_BYPASS_ALLOWCONN</literal>

is specified as <varname>flags</varname> it is possible to bypass the restriction

to connect to databases not allowing user connections.

A background worker can only call one of these two functions, and only

once. It is not possible to switch databases.

</para>