diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index e88c45d..8c32d6c 100644
*** a/src/backend/utils/cache/lsyscache.c
--- b/src/backend/utils/cache/lsyscache.c
***************
*** 46,51 ****
--- 46,54 ----
  #include "utils/syscache.h"
  #include "utils/typcache.h"
  
+ /* GUC to force functions to be treated as leakproof */
+ extern bool		force_leakproof;
+ 
  /* Hook for plugins to get control in get_attavgwidth() */
  get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
  
*************** get_func_leakproof(Oid funcid)
*** 1595,1600 ****
--- 1598,1610 ----
  	HeapTuple	tp;
  	bool		result;
  
+ 	/*
+ 	 * If client message suppression was requested,
+ 	 * treat all functions as leakproof
+ 	 */
+ 	if (force_leakproof)
+ 		return true;
+ 
  	tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  	if (!HeapTupleIsValid(tp))
  		elog(ERROR, "cache lookup failed for function %u", funcid);
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 8b4720e..9941756 100644
*** a/src/backend/utils/error/elog.c
--- b/src/backend/utils/error/elog.c
*************** int			Log_destination = LOG_DESTINATION_
*** 107,112 ****
--- 107,113 ----
  char	   *Log_destination_string = NULL;
  bool		syslog_sequence_numbers = true;
  bool		syslog_split_messages = true;
+ bool		suppress_client_messages = false;
  
  #ifdef HAVE_SYSLOG
  
*************** send_message_to_frontend(ErrorData *edat
*** 3166,3189 ****
  
  		/* M field is required per protocol, so always send something */
  		pq_sendbyte(&msgbuf, PG_DIAG_MESSAGE_PRIMARY);
- 		if (edata->message)
- 			err_sendstring(&msgbuf, edata->message);
- 		else
- 			err_sendstring(&msgbuf, _("missing error text"));
  
! 		if (edata->detail)
  		{
! 			pq_sendbyte(&msgbuf, PG_DIAG_MESSAGE_DETAIL);
! 			err_sendstring(&msgbuf, edata->detail);
! 		}
  
! 		/* detail_log is intentionally not used here */
  
! 		if (edata->hint)
! 		{
! 			pq_sendbyte(&msgbuf, PG_DIAG_MESSAGE_HINT);
! 			err_sendstring(&msgbuf, edata->hint);
  		}
  
  		if (edata->context)
  		{
--- 3167,3197 ----
  
  		/* M field is required per protocol, so always send something */
  		pq_sendbyte(&msgbuf, PG_DIAG_MESSAGE_PRIMARY);
  
! 		/* skip sending if requested */
! 		if (!suppress_client_messages)
  		{
! 			if (edata->message)
! 				err_sendstring(&msgbuf, edata->message);
! 			else
! 				err_sendstring(&msgbuf, _("missing error text"));
  
! 			if (edata->detail)
! 			{
! 				pq_sendbyte(&msgbuf, PG_DIAG_MESSAGE_DETAIL);
! 				err_sendstring(&msgbuf, edata->detail);
! 			}
  
! 			/* detail_log is intentionally not used here */
! 
! 			if (edata->hint)
! 			{
! 				pq_sendbyte(&msgbuf, PG_DIAG_MESSAGE_HINT);
! 				err_sendstring(&msgbuf, edata->hint);
! 			}
  		}
+ 		else
+ 			err_sendstring(&msgbuf, _("redacted message text"));
  
  		if (edata->context)
  		{
*************** send_message_to_frontend(ErrorData *edat
*** 3274,3283 ****
  		if (edata->show_funcname && edata->funcname)
  			appendStringInfo(&buf, "%s: ", edata->funcname);
  
! 		if (edata->message)
! 			appendStringInfoString(&buf, edata->message);
  		else
! 			appendStringInfoString(&buf, _("missing error text"));
  
  		if (edata->cursorpos > 0)
  			appendStringInfo(&buf, _(" at character %d"),
--- 3282,3297 ----
  		if (edata->show_funcname && edata->funcname)
  			appendStringInfo(&buf, "%s: ", edata->funcname);
  
! 		/* skip sending if requested */
! 		if (!suppress_client_messages)
! 		{
! 			if (edata->message)
! 				appendStringInfoString(&buf, edata->message);
! 			else
! 				appendStringInfoString(&buf, _("missing error text"));
! 		}
  		else
! 			appendStringInfoString(&buf, _("redacted message text"));
  
  		if (edata->cursorpos > 0)
  			appendStringInfo(&buf, _(" at character %d"),
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 156d147..e8a1617 100644
*** a/src/backend/utils/misc/guc.c
--- b/src/backend/utils/misc/guc.c
*************** char	   *event_source;
*** 495,500 ****
--- 495,501 ----
  
  bool		row_security;
  bool		check_function_bodies = true;
+ bool		force_leakproof;
  
  /*
   * This GUC exists solely for backward compatibility, check its definition for
*************** static struct config_bool ConfigureNames
*** 1911,1916 ****
--- 1912,1935 ----
  		false,
  		NULL, NULL, NULL
  	},
+ 
+ 	{
+ 		{"suppress_client_messages", PGC_POSTMASTER, ERROR_HANDLING_OPTIONS,
+ 			gettext_noop("Suppress all client messages."),
+ 		},
+ 		&suppress_client_messages,
+ 		false,
+ 		NULL, NULL, NULL
+ 	},
+ 
+ 	{
+ 		{"force_leakproof", PGC_POSTMASTER, ERROR_HANDLING_OPTIONS,
+ 			gettext_noop("Force all functions to behave as if leakproof."),
+ 		},
+ 		&force_leakproof,
+ 		false,
+ 		NULL, NULL, NULL
+ 	},
  
  	/* End-of-list marker */
  	{
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 7ac37fd..11e9897 100644
*** a/src/include/utils/elog.h
--- b/src/include/utils/elog.h
*************** extern int	Log_destination;
*** 407,412 ****
--- 407,413 ----
  extern char *Log_destination_string;
  extern bool syslog_sequence_numbers;
  extern bool syslog_split_messages;
+ extern bool suppress_client_messages;
  
  /* Log destination bitmap */
  #define LOG_DESTINATION_STDERR	 1