diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
new file mode 100644
index 6fcd909..3c14ddc
*** a/src/backend/commands/async.c
--- b/src/backend/commands/async.c
***************
*** 134,139 ****
--- 134,141 ----
  #include "utils/ps_status.h"
  #include "utils/timestamp.h"
  
+ int                  JJNOTDUP=0;
+ 
  
  /*
   * Maximum size of a NOTIFY payload, including terminating NULL.  This
*************** AsyncExistsPendingNotify(const char *cha
*** 2168,2174 ****
  	ListCell   *p;
  	Notification *n;
  
! 	if (pendingNotifies == NIL)
  		return false;
  
  	if (payload == NULL)
--- 2170,2176 ----
  	ListCell   *p;
  	Notification *n;
  
! 	if (pendingNotifies == NIL || JJNOTDUP)
  		return false;
  
  	if (payload == NULL)
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
new file mode 100644
index ceca0d5..183085d
*** a/src/backend/utils/misc/guc.c
--- b/src/backend/utils/misc/guc.c
***************
*** 125,130 ****
--- 125,133 ----
  #define S_PER_D (60 * 60 * 24)
  #define MS_PER_D (1000 * 60 * 60 * 24)
  
+ 
+ extern int JJNOTDUP;
+ 
  /* XXX these should appear in other modules' header files */
  extern bool Log_disconnections;
  extern int	CommitDelay;
*************** static struct config_bool ConfigureNames
*** 1459,1464 ****
--- 1462,1476 ----
  static struct config_int ConfigureNamesInt[] =
  {
  	{
+ 		{"JJNOTDUP",  PGC_USERSET, RESOURCES_ASYNCHRONOUS,
+ 			gettext_noop("Do not remove duplicates for NOTIFY queue"),
+ 			NULL
+ 		},
+ 		&JJNOTDUP,
+ 		0, 0, INT_MAX,
+ 		NULL, NULL, NULL
+ 	},
+ 	{
  		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
  			gettext_noop("Forces a switch to the next xlog file if a "
  						 "new file has not been started within N seconds."),