diff --git a/pg_stat_monitor--1.0--2.0.sql b/pg_stat_monitor--1.0--2.0.sql
index dbfc8bb..5c2cbfa 100644
--- a/pg_stat_monitor--1.0--2.0.sql
+++ b/pg_stat_monitor--1.0--2.0.sql
@@ -30,7 +30,7 @@ CREATE FUNCTION pg_stat_monitor_internal(
 	OUT elevel              int,
     OUT sqlcode             TEXT,
     OUT message             text,
-    OUT bucket_start_time   text,
+    OUT bucket_start_time   timestamp,
 
 	OUT calls         		int8,  -- 16
 
diff --git a/pg_stat_monitor--1.0.sql b/pg_stat_monitor--1.0.sql
index 0321479..186d29a 100644
--- a/pg_stat_monitor--1.0.sql
+++ b/pg_stat_monitor--1.0.sql
@@ -139,7 +139,7 @@ CREATE FUNCTION pg_stat_monitor_internal(
 	OUT elevel              int,
     OUT sqlcode             TEXT,
     OUT message             text,
-    OUT bucket_start_time   text,
+    OUT bucket_start_time   timestamp,
 
 	OUT calls         		int8,  -- 16
 
@@ -190,7 +190,7 @@ $$
 BEGIN
 CREATE VIEW pg_stat_monitor AS SELECT
     bucket,
-	bucket_start_time AS bucket_start_time,
+	bucket_start_time::text AS bucket_start_time,
     userid::regrole,
     datname,
 	'0.0.0.0'::inet + client_ip AS client_ip,
@@ -247,7 +247,7 @@ $$
 BEGIN
 CREATE VIEW pg_stat_monitor AS SELECT
     bucket,
-	bucket_start_time AS bucket_start_time,
+	bucket_start_time::text AS bucket_start_time,
     userid::regrole,
     datname,
 	'0.0.0.0'::inet + client_ip AS client_ip,
@@ -307,7 +307,7 @@ $$
 BEGIN
 CREATE VIEW pg_stat_monitor AS SELECT
     bucket,
-	bucket_start_time AS bucket_start_time,
+	bucket_start_time::text AS bucket_start_time,
     userid::regrole,
     datname,
 	'0.0.0.0'::inet + client_ip AS client_ip,
diff --git a/pg_stat_monitor--2.0.sql b/pg_stat_monitor--2.0.sql
index 339469a..1e87873 100644
--- a/pg_stat_monitor--2.0.sql
+++ b/pg_stat_monitor--2.0.sql
@@ -126,7 +126,7 @@ CREATE FUNCTION pg_stat_monitor_internal(
 	OUT elevel              int,
     OUT sqlcode             TEXT,
     OUT message             text,
-    OUT bucket_start_time   text,
+    OUT bucket_start_time   timestamp,
 
 	OUT calls         		int8,  -- 16
 
diff --git a/pg_stat_monitor.c b/pg_stat_monitor.c
index 76cf180..6a22bdc 100644
--- a/pg_stat_monitor.c
+++ b/pg_stat_monitor.c
@@ -1845,7 +1845,7 @@ pg_stat_monitor_internal(FunctionCallInfo fcinfo,
 			values[i++] = CStringGetTextDatum(tmp.error.message);
 
 		/* bucket_start_time at column number 15 */
-		values[i++] = CStringGetTextDatum(pgss->bucket_start_time[entry->key.bucket_id]);
+		values[i++] = CStringGetDatum(pgss->bucket_start_time[entry->key.bucket_id]);
 		if (tmp.calls.calls == 0)
 		{
 			/* Query of pg_stat_monitor itslef started from zero count */