From d1e027221d0243b7b57eabb0e482923dd7d1c8eb Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Tue, 16 Feb 2010 22:34:57 +0000
Subject: Replace the pg_listener-based LISTEN/NOTIFY mechanism with an
 in-memory queue. In addition, add support for a "payload" string to be passed
 along with each notify event.

This implementation should be significantly more efficient than the old one,
and is also more compatible with Hot Standby usage.  There is not yet any
facility for HS slaves to receive notifications generated on the master,
although such a thing is possible in future.

Joachim Wieland, reviewed by Jeff Davis; also hacked on by me.
---
 src/backend/parser/gram.y | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

(limited to 'src/backend/parser')

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index da70ee089c5..235a7001adf 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.708 2010/02/12 17:33:20 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.709 2010/02/16 22:34:49 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -400,7 +400,7 @@ static TypeName *TableFuncTypeName(List *columns);
 
 %type <ival>	Iconst SignedIconst
 %type <list>	Iconst_list
-%type <str>		Sconst comment_text
+%type <str>		Sconst comment_text notify_payload
 %type <str>		RoleId opt_granted_by opt_boolean ColId_or_Sconst
 %type <list>	var_list
 %type <str>		ColId ColLabel var_name type_function_name param_name
@@ -6123,14 +6123,20 @@ DropRuleStmt:
  *
  *****************************************************************************/
 
-NotifyStmt: NOTIFY ColId
+NotifyStmt: NOTIFY ColId notify_payload
 				{
 					NotifyStmt *n = makeNode(NotifyStmt);
 					n->conditionname = $2;
+					n->payload = $3;
 					$$ = (Node *)n;
 				}
 		;
 
+notify_payload:
+			',' Sconst							{ $$ = $2; }
+			| /*EMPTY*/							{ $$ = NULL; }
+		;
+
 ListenStmt: LISTEN ColId
 				{
 					ListenStmt *n = makeNode(ListenStmt);
-- 
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