diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
index 233ac50d7e6..bde6d786ae6 100644
--- a/src/test/regress/expected/timestamp.out
+++ b/src/test/regress/expected/timestamp.out
@@ -234,7 +234,7 @@ SELECT d1 FROM TIMESTAMP_TBL;
  Mon Jan 01 17:32:01 2001
 (65 rows)
 
--- Check behavior at the lower boundary of the timestamp range
+-- Check behavior at the boundaries of the timestamp range
 SELECT '4714-11-24 00:00:00 BC'::timestamp;
           timestamp          
 -----------------------------
@@ -245,7 +245,16 @@ SELECT '4714-11-23 23:59:59 BC'::timestamp;  -- out of range
 ERROR:  timestamp out of range: "4714-11-23 23:59:59 BC"
 LINE 1: SELECT '4714-11-23 23:59:59 BC'::timestamp;
                ^
--- The upper boundary differs between integer and float timestamps, so no check
+SELECT '294276-12-31 23:59:59'::timestamp;
+         timestamp          
+----------------------------
+ Sun Dec 31 23:59:59 294276
+(1 row)
+
+SELECT '294277-01-01 00:00:00'::timestamp;  -- out of range
+ERROR:  timestamp out of range: "294277-01-01 00:00:00"
+LINE 1: SELECT '294277-01-01 00:00:00'::timestamp;
+               ^
 -- Demonstrate functions and operators
 SELECT d1 FROM TIMESTAMP_TBL
    WHERE d1 > timestamp without time zone '1997-01-02';
diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out
index abd8a645a0a..752333f0b00 100644
--- a/src/test/regress/expected/timestamptz.out
+++ b/src/test/regress/expected/timestamptz.out
@@ -318,7 +318,7 @@ SELECT d1 FROM TIMESTAMPTZ_TBL;
  Mon Jan 01 17:32:01 2001 PST
 (66 rows)
 
--- Check behavior at the lower boundary of the timestamp range
+-- Check behavior at the boundaries of the timestamp range
 SELECT '4714-11-24 00:00:00+00 BC'::timestamptz;
            timestamptz           
 ---------------------------------
@@ -341,7 +341,26 @@ SELECT '4714-11-23 23:59:59+00 BC'::timestamptz;  -- out of range
 ERROR:  timestamp out of range: "4714-11-23 23:59:59+00 BC"
 LINE 1: SELECT '4714-11-23 23:59:59+00 BC'::timestamptz;
                ^
--- The upper boundary differs between integer and float timestamps, so no check
+SELECT '294276-12-31 23:59:59+00'::timestamptz;
+          timestamptz           
+--------------------------------
+ Sun Dec 31 15:59:59 294276 PST
+(1 row)
+
+SELECT '294276-12-31 15:59:59-08'::timestamptz;
+          timestamptz           
+--------------------------------
+ Sun Dec 31 15:59:59 294276 PST
+(1 row)
+
+SELECT '294277-01-01 00:00:00+00'::timestamptz;  -- out of range
+ERROR:  timestamp out of range: "294277-01-01 00:00:00+00"
+LINE 1: SELECT '294277-01-01 00:00:00+00'::timestamptz;
+               ^
+SELECT '294277-12-31 16:00:00-08'::timestamptz;  -- out of range
+ERROR:  timestamp out of range: "294277-12-31 16:00:00-08"
+LINE 1: SELECT '294277-12-31 16:00:00-08'::timestamptz;
+               ^
 -- Demonstrate functions and operators
 SELECT d1 FROM TIMESTAMPTZ_TBL
    WHERE d1 > timestamp with time zone '1997-01-02';
diff --git a/src/test/regress/sql/timestamp.sql b/src/test/regress/sql/timestamp.sql
index 78116a38e83..458a16b5c61 100644
--- a/src/test/regress/sql/timestamp.sql
+++ b/src/test/regress/sql/timestamp.sql
@@ -137,10 +137,11 @@ INSERT INTO TIMESTAMP_TBL VALUES ('Feb 16 17:32:01 5097 BC');
 
 SELECT d1 FROM TIMESTAMP_TBL;
 
--- Check behavior at the lower boundary of the timestamp range
+-- Check behavior at the boundaries of the timestamp range
 SELECT '4714-11-24 00:00:00 BC'::timestamp;
 SELECT '4714-11-23 23:59:59 BC'::timestamp;  -- out of range
--- The upper boundary differs between integer and float timestamps, so no check
+SELECT '294276-12-31 23:59:59'::timestamp;
+SELECT '294277-01-01 00:00:00'::timestamp;  -- out of range
 
 -- Demonstrate functions and operators
 SELECT d1 FROM TIMESTAMP_TBL
diff --git a/src/test/regress/sql/timestamptz.sql b/src/test/regress/sql/timestamptz.sql
index 7ad6edcd61c..d21a8a4dff0 100644
--- a/src/test/regress/sql/timestamptz.sql
+++ b/src/test/regress/sql/timestamptz.sql
@@ -158,12 +158,15 @@ SELECT 'Wed Jul 11 10:51:14 PST+03:00 2001'::timestamptz;
 
 SELECT d1 FROM TIMESTAMPTZ_TBL;
 
--- Check behavior at the lower boundary of the timestamp range
+-- Check behavior at the boundaries of the timestamp range
 SELECT '4714-11-24 00:00:00+00 BC'::timestamptz;
 SELECT '4714-11-23 16:00:00-08 BC'::timestamptz;
 SELECT 'Sun Nov 23 16:00:00 4714 PST BC'::timestamptz;
 SELECT '4714-11-23 23:59:59+00 BC'::timestamptz;  -- out of range
--- The upper boundary differs between integer and float timestamps, so no check
+SELECT '294276-12-31 23:59:59+00'::timestamptz;
+SELECT '294276-12-31 15:59:59-08'::timestamptz;
+SELECT '294277-01-01 00:00:00+00'::timestamptz;  -- out of range
+SELECT '294277-12-31 16:00:00-08'::timestamptz;  -- out of range
 
 -- Demonstrate functions and operators
 SELECT d1 FROM TIMESTAMPTZ_TBL