Implement dblink_get_notify().

Adds the ability to retrieve async notifications using dblink,
via the addition of the function dblink_get_notify(). Original patch
by Marcus Kempe, suggestions by Tom Lane and Alvaro Herrera, patch
review and adjustments by Joe Conway.

1 files changed, 51 insertions, 0 deletions

diff --git a/contrib/dblink/expected/dblink.out b/contrib/dblink/expected/dblink.out
index 102444d88c..13e4a6fb4c 100644
--- a/contrib/dblink/expected/dblink.out
+++ b/contrib/dblink/expected/dblink.out
@@ -827,3 +827,54 @@ DROP USER dblink_regression_test;
 DROP USER MAPPING FOR public SERVER fdtest;
 DROP SERVER fdtest;
 DROP FOREIGN DATA WRAPPER postgresql;
+-- test asynchronous notifications
+SELECT dblink_connect('dbname=contrib_regression');
+ dblink_connect
+----------------
+ OK
+(1 row)
+
+--should return listen
+SELECT dblink_exec('LISTEN regression');
+ dblink_exec
+-------------
+ LISTEN
+(1 row)
+
+--should return listen
+SELECT dblink_exec('LISTEN foobar');
+ dblink_exec
+-------------
+ LISTEN
+(1 row)
+
+SELECT dblink_exec('NOTIFY regression');
+ dblink_exec
+-------------
+ NOTIFY
+(1 row)
+
+SELECT dblink_exec('NOTIFY foobar');
+ dblink_exec
+-------------
+ NOTIFY
+(1 row)
+
+SELECT notify_name, be_pid = (select t.be_pid from dblink('select pg_backend_pid()') as t(be_pid int)) AS is_self_notify, extra from dblink_get_notify();
+ notify_name | is_self_notify | extra
+-------------+----------------+-------
+ regression  | t              |
+ foobar      | t              |
+(2 rows)
+
+SELECT * from dblink_get_notify();
+ notify_name | be_pid | extra
+-------------+--------+-------
+(0 rows)
+
+SELECT dblink_disconnect();
+ dblink_disconnect
+-------------------
+ OK
+(1 row)
+