diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index bbe9388..5494c96 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -121,8 +121,10 @@ typedef enum
 /* pgpool-II extension. This is same as ERROR but sets the
  * do not cache connection flag before transforming to ERROR.
  */
-#define FRONTEND_ERROR			23	/* transformed to ERROR at errstart */
-#define FRONTEND_ONLY_ERROR		24	/* this is treated as LOG message
+#define FRONTEND_DEBUG			23	/* transformed to DEBUG at errstart */
+#define FRONTEND_LOG			24	/* transformed to LOG at errstart */
+#define FRONTEND_ERROR			25	/* transformed to ERROR at errstart */
+#define FRONTEND_ONLY_ERROR		26	/* this is treated as LOG message
 									 * internally for pgpool-II but forwarded
 									 * to frontend clients just like normal
 									 * errors followed by readyForQuery
diff --git a/src/include/utils/fe_ports.h b/src/include/utils/fe_ports.h
index ddbd462..6b0e488 100644
--- a/src/include/utils/fe_ports.h
+++ b/src/include/utils/fe_ports.h
@@ -113,8 +113,10 @@ extern void errfinish(int dummy,...);
 #define FATAL		21			/* fatal error - abort process */
 #define PANIC		22			/* take down the other backends with me */
 
-#define FRONTEND_ERROR			23	/* transformed to ERROR at errstart */
-#define FRONTEND_ONLY_ERROR		24	/* this is treated as LOG message
+#define FRONTEND_DEBUG			23	/* transformed to DEBUG at errstart */
+#define FRONTEND_LOG			24	/* transformed to LOG at errstart */
+#define FRONTEND_ERROR			25	/* transformed to ERROR at errstart */
+#define FRONTEND_ONLY_ERROR		26	/* this is treated as LOG message
 									 * internally for pgpool-II but forwarded
 									 * to frontend clients just like normal
 									 * errors followed by readyForQuery
diff --git a/src/protocol/pool_process_query.c b/src/protocol/pool_process_query.c
index 07dcc0b..fc2d222 100644
--- a/src/protocol/pool_process_query.c
+++ b/src/protocol/pool_process_query.c
@@ -571,8 +571,8 @@ wait_for_query_response(POOL_CONNECTION * frontend, POOL_CONNECTION * backend, i
 				pool_write(frontend, DUMMY_VALUE, sizeof(DUMMY_VALUE));
 				if (pool_flush_it(frontend) < 0)
 				{
-					ereport(FRONTEND_ERROR,
-							(errmsg("unable to to flush data to frontend"),
+					ereport(FRONTEND_DEBUG,
+							(errmsg("unable to flush data to frontend"),
 							 errdetail("frontend error occurred while waiting for backend reply")));
 				}
 
@@ -595,8 +595,8 @@ wait_for_query_response(POOL_CONNECTION * frontend, POOL_CONNECTION * backend, i
 				pool_write(frontend, notice_message, strlen(notice_message) + 1);
 				if (pool_flush_it(frontend) < 0)
 				{
-					ereport(FRONTEND_ERROR,
-							(errmsg("unable to to flush data to frontend"),
+					ereport(FRONTEND_DEBUG,
+							(errmsg("unable to flush data to frontend"),
 							 errdetail("frontend error occurred while waiting for backend reply")));
 
 				}
@@ -4922,7 +4922,7 @@ SELECT_RETRY:
 
 			if (idle_count > pool_config->client_idle_limit)
 			{
-				ereport(FRONTEND_ERROR,
+				ereport(FRONTEND_DEBUG,
 						(pool_error_code("57000"),
 						 errmsg("unable to read data"),
 						 errdetail("child connection forced to terminate due to client_idle_limit:%d is reached",
@@ -4935,7 +4935,7 @@ SELECT_RETRY:
 
 			if (idle_count_in_recovery > pool_config->client_idle_limit_in_recovery)
 			{
-				ereport(FRONTEND_ERROR,
+				ereport(FRONTEND_DEBUG,
 						(pool_error_code("57000"),
 						 errmsg("unable to read data"),
 						 errdetail("child connection forced to terminate due to client_idle_limit_in_recovery:%d is reached", pool_config->client_idle_limit_in_recovery)));
@@ -4947,7 +4947,7 @@ SELECT_RETRY:
 			 * If we are in recovery and client_idle_limit_in_recovery is -1,
 			 * then exit immediately.
 			 */
-			ereport(FRONTEND_ERROR,
+			ereport(FRONTEND_DEBUG,
 					(pool_error_code("57000"),
 					 errmsg("connection terminated due to online recovery"),
 					 errdetail("child connection forced to terminate due to client_idle_limit:-1")));
diff --git a/src/tools/fe_port.c b/src/tools/fe_port.c
index 7c30573..6b95c29 100644
--- a/src/tools/fe_port.c
+++ b/src/tools/fe_port.c
@@ -118,10 +118,12 @@ error_severity(int elevel)
 		case DEBUG3:
 		case DEBUG4:
 		case DEBUG5:
+		case FRONTEND_DEBUG:
 			prefix = "DEBUG";
 			break;
 		case LOG:
 		case COMMERROR:
+		case FRONTEND_LOG:
 			prefix = "LOG";
 			break;
 		case INFO:
diff --git a/src/utils/error/elog.c b/src/utils/error/elog.c
index 44061c6..9d4c145 100644
--- a/src/utils/error/elog.c
+++ b/src/utils/error/elog.c
@@ -202,11 +202,16 @@ static inline bool should_output_to_client(int elevel);
 static bool
 is_log_level_output(int elevel, int log_min_level)
 {
-	if (elevel == LOG || elevel == COMMERROR || elevel == FRONTEND_ONLY_ERROR)
+	if (elevel == LOG || elevel == COMMERROR || elevel == FRONTEND_ONLY_ERROR || elevel == FRONTEND_LOG)
 	{
 		if (log_min_level == LOG || log_min_level <= ERROR)
 			return true;
 	}
+	else if (elevel == FRONTEND_DEBUG)
+	{
+		if (log_min_level <= DEBUG1)
+			return true;
+	}
 	else if (log_min_level == LOG)
 	{
 		/* elevel != LOG */
@@ -313,6 +318,10 @@ errstart(int elevel, const char *filename, int lineno,
 		frontend_invalid = true;
 		elevel = ERROR;
 	}
+	else if (elevel == FRONTEND_DEBUG || elevel == FRONTEND_LOG)
+	{
+		frontend_invalid = true;
+	}
 
 	if (elevel >= ERROR && elevel != FRONTEND_ONLY_ERROR)
 	{
@@ -328,7 +337,7 @@ errstart(int elevel, const char *filename, int lineno,
 		 * proc_exit's responsibility to see that this doesn't turn into
 		 * infinite recursion!)
 		 */
-		if (elevel == ERROR)
+		if (elevel == ERROR || elevel == FRONTEND_LOG || elevel == FRONTEND_DEBUG)
 		{
 			if (PG_exception_stack == NULL ||
 				proc_exit_inprogress)
@@ -477,7 +486,7 @@ errfinish(int dummy,...)
 	 * If ERROR (not more nor less) we pass it off to the current handler.
 	 * Printing it and popping the stack is the responsibility of the handler.
 	 */
-	if (elevel == ERROR)
+	if (elevel == ERROR || elevel == FRONTEND_LOG || elevel == FRONTEND_DEBUG)
 	{
 		/*
 		 * We do some minimal cleanup before longjmp'ing so that handlers can
@@ -1691,6 +1700,8 @@ write_eventlog(int level, const char *line, int len)
 		case DEBUG1:
 		case LOG:
 		case COMMERROR:
+		case FRONTEND_LOG:
+		case FRONTEND_DEBUG:
 		case INFO:
 		case NOTICE:
 			eventlevel = EVENTLOG_INFORMATION_TYPE;
@@ -2325,11 +2336,13 @@ send_message_to_server_log(ErrorData *edata)
 			case DEBUG3:
 			case DEBUG2:
 			case DEBUG1:
+			case FRONTEND_DEBUG:
 				syslog_level = LOG_DEBUG;
 				break;
 			case LOG:
 			case COMMERROR:
 			case INFO:
+			case FRONTEND_LOG:
 				syslog_level = LOG_INFO;
 				break;
 			case NOTICE:
@@ -2472,10 +2485,12 @@ error_severity(int elevel, bool for_frontend)
 		case DEBUG3:
 		case DEBUG4:
 		case DEBUG5:
+		case FRONTEND_DEBUG:
 			prefix = _("DEBUG");
 			break;
 		case LOG:
 		case COMMERROR:
+		case FRONTEND_LOG:
 			prefix = _("LOG");
 			break;
 		case INFO:
diff --git a/src/utils/pool_stream.c b/src/utils/pool_stream.c
index 2eafd96..8ed49a7 100644
--- a/src/utils/pool_stream.c
+++ b/src/utils/pool_stream.c
@@ -256,7 +256,7 @@ pool_read(POOL_CONNECTION * cp, void *buf, int len)
 			}
 			else
 			{
-				ereport(FRONTEND_ERROR,
+				ereport(FRONTEND_DEBUG,
 						(errmsg("unable to read data from frontend"),
 						 errdetail("socket read failed with error \"%m\"")));
 			}
@@ -281,7 +281,7 @@ pool_read(POOL_CONNECTION * cp, void *buf, int len)
 				 * if backend offers authentication method, frontend could
 				 * close connection
 				 */
-				ereport(FRONTEND_ERROR,
+				ereport(FRONTEND_DEBUG,
 						(errmsg("unable to read data from frontend"),
 						 errdetail("EOF encountered with frontend")));
 			}
@@ -776,7 +776,7 @@ pool_flush(POOL_CONNECTION * cp)
 						(errmsg("unable to flush data to frontend"),
 						 errdetail("pgpool is in replication mode, ignoring error to keep consistency among backends")));
 			else
-				ereport(FRONTEND_ERROR,
+				ereport(FRONTEND_DEBUG,
 						(errmsg("unable to flush data to frontend")));
 
 		}