<literal>BGWH_POSTMASTER_DIED</literal>.

</para>

<para>

If a background worker sends asynchronous notifications with the

<command>NOTIFY</command> command via the Server Programming Interface

(<acronym>SPI</acronym>), it should call

<function>ProcessCompletedNotifies</function> explicitly after committing

the enclosing transaction so that any notifications can be delivered. If a

background worker registers to receive asynchronous notifications with

the <command>LISTEN</command> through <acronym>SPI</acronym>, the worker

will log those notifications, but there is no programmatic way for the

worker to intercept and respond to those notifications.

</para>

<para>

The <filename>worker_spi</> contrib module contains a working example,

which demonstrates some useful techniques.