From dde5f09fad3ac188a155e21667f76825f43a28c8 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 6 Nov 2015 00:31:03 -0500
Subject: [PATCH] Document interaction of bgworkers with LISTEN/NOTIFY.
Thomas Munro and Robert Haas, reviewed by Haribabu Kommi
---
doc/src/sgml/bgworker.sgml | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/doc/src/sgml/bgworker.sgml b/doc/src/sgml/bgworker.sgml
index 505e362879a..5570ed045db 100644
--- a/doc/src/sgml/bgworker.sgml
+++ b/doc/src/sgml/bgworker.sgml
@@ -277,6 +277,18 @@ typedef struct BackgroundWorker
<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.
--
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