Document interaction of bgworkers with LISTEN/NOTIFY.

Thomas Munro and Robert Haas, reviewed by Haribabu Kommi

diff --git a/doc/src/sgml/bgworker.sgml b/doc/src/sgml/bgworker.sgml
index 505e362879ad10edd8c42633a39d00de61bbc83c..5570ed045dbc4e5e9bbc243261be1e8594e85216 100644 (file)
--- a/doc/src/sgml/bgworker.sgml
+++ b/doc/src/sgml/bgworker.sgml
@@ -277,6 +277,18 @@ typedef struct BackgroundWorker
    BGWH_POSTMASTER_DIED.
   
 
+  
+   If a background worker sends asynchronous notifications with the
+   NOTIFY command via the Server Programming Interface
+   (SPI), it should call
+   ProcessCompletedNotifies explicitly after committing
+   the enclosing transaction so that any notifications can be delivered.  If a
+   background worker registers to receive asynchronous notifications with
+   the LISTEN through SPI, the worker
+   will log those notifications, but there is no programmatic way for the
+   worker to intercept and respond to those notifications.
+  
+
   
    The worker_spi contrib module contains a working example,
    which demonstrates some useful techniques.