Change return type of EXTRACT to numeric

The previous implementation of EXTRACT mapped internally to
date_part(), which returned type double precision (since it was
implemented long before the numeric type existed).  This can lead to
imprecise output in some cases, so returning numeric would be
preferrable.  Changing the return type of an existing function is a
bit risky, so instead we do the following:  We implement a new set of
functions, which are now called "extract", in parallel to the existing
date_part functions.  They work the same way internally but use
numeric instead of float8.  The EXTRACT construct is now mapped by the
parser to these new extract functions.  That way, dumps of views
etc. from old versions (which would use date_part) continue to work
unchanged, but new uses will map to the new extract functions.

Additionally, the reverse compilation of EXTRACT now reproduces the
original syntax, using the new mechanism introduced in
40c24bfef92530bd846e111c1742c2a54441c62c.

The following minor changes of behavior result from the new
implementation:

- The column name from an isolated EXTRACT call is now "extract"
  instead of "date_part".

- Extract from date now rejects inappropriate field names such as
  HOUR.  It was previously mapped internally to extract from
  timestamp, so it would silently accept everything appropriate for
  timestamp.

- Return values when extracting fields with possibly fractional
  values, such as second and epoch, now have the full scale that the
  value has internally (so, for example, '1.000000' instead of just
  '1').

Reported-by: Petr Fedorov <[email protected]>
Reviewed-by: Tom Lane <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/[email protected]

14 files changed, 598 insertions, 334 deletions

diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out
index 87fd2fbfd00..f50ef766857 100644
--- a/src/test/regress/expected/create_view.out
+++ b/src/test/regress/expected/create_view.out
@@ -1787,7 +1787,7 @@ select
 select pg_get_viewdef('tt201v', true);
                                         pg_get_viewdef                                         
 -----------------------------------------------------------------------------------------------
-  SELECT date_part('day'::text, now()) AS extr,                                               +
+  SELECT EXTRACT(day FROM now()) AS extr,                                                     +
      ((now(), '@ 1 day'::interval) OVERLAPS (CURRENT_TIMESTAMP(2), '@ 1 day'::interval)) AS o,+
      (('foo'::text) IS NORMALIZED) AS isn,                                                    +
      (('foo'::text) IS NFKC NORMALIZED) AS isnn,                                              +
diff --git a/src/test/regress/expected/date.out b/src/test/regress/expected/date.out
index 83ad111f1c8..c8b0566ff40 100644
--- a/src/test/regress/expected/date.out
+++ b/src/test/regress/expected/date.out
@@ -966,66 +966,66 @@ SELECT f1 as "date",
 -- epoch
 --
 SELECT EXTRACT(EPOCH FROM DATE        '1970-01-01');     --  0
- date_part 
------------
-         0
+ extract 
+---------
+       0
 (1 row)
 
 --
 -- century
 --
 SELECT EXTRACT(CENTURY FROM DATE '0101-12-31 BC'); -- -2
- date_part 
------------
-        -2
+ extract 
+---------
+      -2
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '0100-12-31 BC'); -- -1
- date_part 
------------
-        -1
+ extract 
+---------
+      -1
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '0001-12-31 BC'); -- -1
- date_part 
------------
-        -1
+ extract 
+---------
+      -1
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '0001-01-01');    --  1
- date_part 
------------
-         1
+ extract 
+---------
+       1
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '0001-01-01 AD'); --  1
- date_part 
------------
-         1
+ extract 
+---------
+       1
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '1900-12-31');    -- 19
- date_part 
------------
-        19
+ extract 
+---------
+      19
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '1901-01-01');    -- 20
- date_part 
------------
-        20
+ extract 
+---------
+      20
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '2000-12-31');    -- 20
- date_part 
------------
-        20
+ extract 
+---------
+      20
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM DATE '2001-01-01');    -- 21
- date_part 
------------
-        21
+ extract 
+---------
+      21
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM CURRENT_DATE)>=21 AS True;     -- true
@@ -1038,217 +1038,218 @@ SELECT EXTRACT(CENTURY FROM CURRENT_DATE)>=21 AS True;     -- true
 -- millennium
 --
 SELECT EXTRACT(MILLENNIUM FROM DATE '0001-12-31 BC'); -- -1
- date_part 
------------
-        -1
+ extract 
+---------
+      -1
 (1 row)
 
 SELECT EXTRACT(MILLENNIUM FROM DATE '0001-01-01 AD'); --  1
- date_part 
------------
-         1
+ extract 
+---------
+       1
 (1 row)
 
 SELECT EXTRACT(MILLENNIUM FROM DATE '1000-12-31');    --  1
- date_part 
------------
-         1
+ extract 
+---------
+       1
 (1 row)
 
 SELECT EXTRACT(MILLENNIUM FROM DATE '1001-01-01');    --  2
- date_part 
------------
-         2
+ extract 
+---------
+       2
 (1 row)
 
 SELECT EXTRACT(MILLENNIUM FROM DATE '2000-12-31');    --  2
- date_part 
------------
-         2
+ extract 
+---------
+       2
 (1 row)
 
 SELECT EXTRACT(MILLENNIUM FROM DATE '2001-01-01');    --  3
- date_part 
------------
-         3
+ extract 
+---------
+       3
 (1 row)
 
 -- next test to be fixed on the turn of the next millennium;-)
 SELECT EXTRACT(MILLENNIUM FROM CURRENT_DATE);         --  3
- date_part 
------------
-         3
+ extract 
+---------
+       3
 (1 row)
 
 --
 -- decade
 --
 SELECT EXTRACT(DECADE FROM DATE '1994-12-25');    -- 199
- date_part 
------------
-       199
+ extract 
+---------
+     199
 (1 row)
 
 SELECT EXTRACT(DECADE FROM DATE '0010-01-01');    --   1
- date_part 
------------
-         1
+ extract 
+---------
+       1
 (1 row)
 
 SELECT EXTRACT(DECADE FROM DATE '0009-12-31');    --   0
- date_part 
------------
-         0
+ extract 
+---------
+       0
 (1 row)
 
 SELECT EXTRACT(DECADE FROM DATE '0001-01-01 BC'); --   0
- date_part 
------------
-         0
+ extract 
+---------
+       0
 (1 row)
 
 SELECT EXTRACT(DECADE FROM DATE '0002-12-31 BC'); --  -1
- date_part 
------------
-        -1
+ extract 
+---------
+      -1
 (1 row)
 
 SELECT EXTRACT(DECADE FROM DATE '0011-01-01 BC'); --  -1
- date_part 
------------
-        -1
+ extract 
+---------
+      -1
 (1 row)
 
 SELECT EXTRACT(DECADE FROM DATE '0012-12-31 BC'); --  -2
- date_part 
------------
-        -2
+ extract 
+---------
+      -2
 (1 row)
 
 --
 -- all possible fields
 --
 SELECT EXTRACT(MICROSECONDS  FROM DATE '2020-08-11');
- date_part 
------------
-         0
-(1 row)
-
+ERROR:  date units "microseconds" not supported
 SELECT EXTRACT(MILLISECONDS  FROM DATE '2020-08-11');
- date_part 
------------
-         0
-(1 row)
-
+ERROR:  date units "milliseconds" not supported
 SELECT EXTRACT(SECOND        FROM DATE '2020-08-11');
- date_part 
------------
-         0
-(1 row)
-
+ERROR:  date units "second" not supported
 SELECT EXTRACT(MINUTE        FROM DATE '2020-08-11');
- date_part 
------------
-         0
-(1 row)
-
+ERROR:  date units "minute" not supported
 SELECT EXTRACT(HOUR          FROM DATE '2020-08-11');
- date_part 
------------
-         0
-(1 row)
-
+ERROR:  date units "hour" not supported
 SELECT EXTRACT(DAY           FROM DATE '2020-08-11');
- date_part 
------------
-        11
+ extract 
+---------
+      11
 (1 row)
 
 SELECT EXTRACT(MONTH         FROM DATE '2020-08-11');
- date_part 
------------
-         8
+ extract 
+---------
+       8
 (1 row)
 
 SELECT EXTRACT(YEAR          FROM DATE '2020-08-11');
- date_part 
------------
-      2020
+ extract 
+---------
+    2020
+(1 row)
+
+SELECT EXTRACT(YEAR          FROM DATE '2020-08-11 BC');
+ extract 
+---------
+   -2020
 (1 row)
 
 SELECT EXTRACT(DECADE        FROM DATE '2020-08-11');
- date_part 
------------
-       202
+ extract 
+---------
+     202
 (1 row)
 
 SELECT EXTRACT(CENTURY       FROM DATE '2020-08-11');
- date_part 
------------
-        21
+ extract 
+---------
+      21
 (1 row)
 
 SELECT EXTRACT(MILLENNIUM    FROM DATE '2020-08-11');
- date_part 
------------
-         3
+ extract 
+---------
+       3
 (1 row)
 
 SELECT EXTRACT(ISOYEAR       FROM DATE '2020-08-11');
- date_part 
------------
-      2020
+ extract 
+---------
+    2020
+(1 row)
+
+SELECT EXTRACT(ISOYEAR       FROM DATE '2020-08-11 BC');
+ extract 
+---------
+   -2020
 (1 row)
 
 SELECT EXTRACT(QUARTER       FROM DATE '2020-08-11');
- date_part 
------------
-         3
+ extract 
+---------
+       3
 (1 row)
 
 SELECT EXTRACT(WEEK          FROM DATE '2020-08-11');
- date_part 
------------
-        33
+ extract 
+---------
+      33
 (1 row)
 
 SELECT EXTRACT(DOW           FROM DATE '2020-08-11');
- date_part 
------------
-         2
+ extract 
+---------
+       2
+(1 row)
+
+SELECT EXTRACT(DOW           FROM DATE '2020-08-16');
+ extract 
+---------
+       0
 (1 row)
 
 SELECT EXTRACT(ISODOW        FROM DATE '2020-08-11');
- date_part 
------------
-         2
+ extract 
+---------
+       2
+(1 row)
+
+SELECT EXTRACT(ISODOW        FROM DATE '2020-08-16');
+ extract 
+---------
+       7
 (1 row)
 
 SELECT EXTRACT(DOY           FROM DATE '2020-08-11');
- date_part 
------------
-       224
+ extract 
+---------
+     224
 (1 row)
 
 SELECT EXTRACT(TIMEZONE      FROM DATE '2020-08-11');
-ERROR:  timestamp units "timezone" not supported
-CONTEXT:  SQL function "date_part" statement 1
+ERROR:  date units "timezone" not supported
 SELECT EXTRACT(TIMEZONE_M    FROM DATE '2020-08-11');
-ERROR:  timestamp units "timezone_m" not supported
-CONTEXT:  SQL function "date_part" statement 1
+ERROR:  date units "timezone_m" not supported
 SELECT EXTRACT(TIMEZONE_H    FROM DATE '2020-08-11');
-ERROR:  timestamp units "timezone_h" not supported
-CONTEXT:  SQL function "date_part" statement 1
+ERROR:  date units "timezone_h" not supported
 SELECT EXTRACT(EPOCH         FROM DATE '2020-08-11');
- date_part  
+  extract   
 ------------
  1597104000
 (1 row)
 
 SELECT EXTRACT(JULIAN        FROM DATE '2020-08-11');
- date_part 
------------
-   2459073
+ extract 
+---------
+ 2459073
 (1 row)
 
 --
@@ -1344,173 +1345,124 @@ select isfinite('infinity'::date), isfinite('-infinity'::date), isfinite('today'
 --
 -- oscillating fields from non-finite date:
 --
-SELECT EXTRACT(HOUR FROM DATE 'infinity');      -- NULL
- date_part 
------------
-          
-(1 row)
-
-SELECT EXTRACT(HOUR FROM DATE '-infinity');     -- NULL
- date_part 
------------
-          
-(1 row)
-
--- all possible fields
-SELECT EXTRACT(MICROSECONDS  FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
-(1 row)
-
-SELECT EXTRACT(MILLISECONDS  FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
-(1 row)
-
-SELECT EXTRACT(SECOND        FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
-(1 row)
-
-SELECT EXTRACT(MINUTE        FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+SELECT EXTRACT(DAY FROM DATE 'infinity');      -- NULL
+ extract 
+---------
+        
 (1 row)
 
-SELECT EXTRACT(HOUR          FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+SELECT EXTRACT(DAY FROM DATE '-infinity');     -- NULL
+ extract 
+---------
+        
 (1 row)
 
+-- all supported fields
 SELECT EXTRACT(DAY           FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+ extract 
+---------
+        
 (1 row)
 
 SELECT EXTRACT(MONTH         FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+ extract 
+---------
+        
 (1 row)
 
 SELECT EXTRACT(QUARTER       FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+ extract 
+---------
+        
 (1 row)
 
 SELECT EXTRACT(WEEK          FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+ extract 
+---------
+        
 (1 row)
 
 SELECT EXTRACT(DOW           FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+ extract 
+---------
+        
 (1 row)
 
 SELECT EXTRACT(ISODOW        FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+ extract 
+---------
+        
 (1 row)
 
 SELECT EXTRACT(DOY           FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
-(1 row)
-
-SELECT EXTRACT(TIMEZONE      FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
-(1 row)
-
-SELECT EXTRACT(TIMEZONE_M    FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
-(1 row)
-
-SELECT EXTRACT(TIMEZONE_H    FROM DATE 'infinity');    -- NULL
- date_part 
------------
-          
+ extract 
+---------
+        
 (1 row)
 
 --
 -- monotonic fields from non-finite date:
 --
 SELECT EXTRACT(EPOCH FROM DATE 'infinity');         --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 SELECT EXTRACT(EPOCH FROM DATE '-infinity');        -- -Infinity
- date_part 
+  extract  
 -----------
  -Infinity
 (1 row)
 
--- all possible fields
+-- all supported fields
 SELECT EXTRACT(YEAR       FROM DATE 'infinity');    --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 SELECT EXTRACT(DECADE     FROM DATE 'infinity');    --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 SELECT EXTRACT(CENTURY    FROM DATE 'infinity');    --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 SELECT EXTRACT(MILLENNIUM FROM DATE 'infinity');    --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 SELECT EXTRACT(JULIAN     FROM DATE 'infinity');    --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 SELECT EXTRACT(ISOYEAR    FROM DATE 'infinity');    --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 SELECT EXTRACT(EPOCH      FROM DATE 'infinity');    --  Infinity
- date_part 
------------
-  Infinity
+ extract  
+----------
+ Infinity
 (1 row)
 
 --
 -- wrong fields from non-finite date:
 --
-SELECT EXTRACT(MICROSEC  FROM DATE 'infinity');     -- ERROR:  timestamp units "microsec" not recognized
-ERROR:  timestamp units "microsec" not recognized
-CONTEXT:  SQL function "date_part" statement 1
+SELECT EXTRACT(MICROSEC  FROM DATE 'infinity');     -- error
+ERROR:  date units "microsec" not recognized
 -- test constructors
 select make_date(2013, 7, 15);
  make_date  
diff --git a/src/test/regress/expected/interval.out b/src/test/regress/expected/interval.out
index c5ffa9f2cc1..01919491376 100644
--- a/src/test/regress/expected/interval.out
+++ b/src/test/regress/expected/interval.out
@@ -948,18 +948,18 @@ SELECT f1,
     EXTRACT(MILLENNIUM FROM f1) AS MILLENNIUM,
     EXTRACT(EPOCH FROM f1) AS EPOCH
     FROM INTERVAL_TBL;
-              f1               | microsecond | millisecond | second | minute | hour | day | month | quarter | year | decade | century | millennium |   epoch    
--------------------------------+-------------+-------------+--------+--------+------+-----+-------+---------+------+--------+---------+------------+------------
- @ 1 min                       |           0 |           0 |      0 |      1 |    0 |   0 |     0 |       1 |    0 |      0 |       0 |          0 |         60
- @ 5 hours                     |           0 |           0 |      0 |      0 |    5 |   0 |     0 |       1 |    0 |      0 |       0 |          0 |      18000
- @ 10 days                     |           0 |           0 |      0 |      0 |    0 |  10 |     0 |       1 |    0 |      0 |       0 |          0 |     864000
- @ 34 years                    |           0 |           0 |      0 |      0 |    0 |   0 |     0 |       1 |   34 |      3 |       0 |          0 | 1072958400
- @ 3 mons                      |           0 |           0 |      0 |      0 |    0 |   0 |     3 |       2 |    0 |      0 |       0 |          0 |    7776000
- @ 14 secs ago                 |   -14000000 |      -14000 |    -14 |      0 |    0 |   0 |     0 |       1 |    0 |      0 |       0 |          0 |        -14
- @ 1 day 2 hours 3 mins 4 secs |     4000000 |        4000 |      4 |      3 |    2 |   1 |     0 |       1 |    0 |      0 |       0 |          0 |      93784
- @ 6 years                     |           0 |           0 |      0 |      0 |    0 |   0 |     0 |       1 |    6 |      0 |       0 |          0 |  189345600
- @ 5 mons                      |           0 |           0 |      0 |      0 |    0 |   0 |     5 |       2 |    0 |      0 |       0 |          0 |   12960000
- @ 5 mons 12 hours             |           0 |           0 |      0 |      0 |   12 |   0 |     5 |       2 |    0 |      0 |       0 |          0 |   13003200
+              f1               | microsecond | millisecond |   second   | minute | hour | day | month | quarter | year | decade | century | millennium |       epoch       
+-------------------------------+-------------+-------------+------------+--------+------+-----+-------+---------+------+--------+---------+------------+-------------------
+ @ 1 min                       |           0 |       0.000 |   0.000000 |      1 |    0 |   0 |     0 |       1 |    0 |      0 |       0 |          0 |         60.000000
+ @ 5 hours                     |           0 |       0.000 |   0.000000 |      0 |    5 |   0 |     0 |       1 |    0 |      0 |       0 |          0 |      18000.000000
+ @ 10 days                     |           0 |       0.000 |   0.000000 |      0 |    0 |  10 |     0 |       1 |    0 |      0 |       0 |          0 |     864000.000000
+ @ 34 years                    |           0 |       0.000 |   0.000000 |      0 |    0 |   0 |     0 |       1 |   34 |      3 |       0 |          0 | 1072224000.000000
+ @ 3 mons                      |           0 |       0.000 |   0.000000 |      0 |    0 |   0 |     3 |       2 |    0 |      0 |       0 |          0 |    7776000.000000
+ @ 14 secs ago                 |   -14000000 |  -14000.000 | -14.000000 |      0 |    0 |   0 |     0 |       1 |    0 |      0 |       0 |          0 |        -14.000000
+ @ 1 day 2 hours 3 mins 4 secs |     4000000 |    4000.000 |   4.000000 |      3 |    2 |   1 |     0 |       1 |    0 |      0 |       0 |          0 |      93784.000000
+ @ 6 years                     |           0 |       0.000 |   0.000000 |      0 |    0 |   0 |     0 |       1 |    6 |      0 |       0 |          0 |  189216000.000000
+ @ 5 mons                      |           0 |       0.000 |   0.000000 |      0 |    0 |   0 |     5 |       2 |    0 |      0 |       0 |          0 |   12960000.000000
+ @ 5 mons 12 hours             |           0 |       0.000 |   0.000000 |      0 |   12 |   0 |     5 |       2 |    0 |      0 |       0 |          0 |   13003200.000000
 (10 rows)
 
 SELECT EXTRACT(FORTNIGHT FROM INTERVAL '2 days');  -- error
@@ -967,50 +967,79 @@ ERROR:  interval units "fortnight" not recognized
 SELECT EXTRACT(TIMEZONE FROM INTERVAL '2 days');  -- error
 ERROR:  interval units "timezone" not supported
 SELECT EXTRACT(DECADE FROM INTERVAL '100 y');
- date_part 
------------
-        10
+ extract 
+---------
+      10
 (1 row)
 
 SELECT EXTRACT(DECADE FROM INTERVAL '99 y');
- date_part 
------------
-         9
+ extract 
+---------
+       9
 (1 row)
 
 SELECT EXTRACT(DECADE FROM INTERVAL '-99 y');
- date_part 
------------
-        -9
+ extract 
+---------
+      -9
 (1 row)
 
 SELECT EXTRACT(DECADE FROM INTERVAL '-100 y');
- date_part 
------------
-       -10
+ extract 
+---------
+     -10
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM INTERVAL '100 y');
- date_part 
------------
-         1
+ extract 
+---------
+       1
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM INTERVAL '99 y');
- date_part 
------------
-         0
+ extract 
+---------
+       0
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM INTERVAL '-99 y');
- date_part 
------------
-         0
+ extract 
+---------
+       0
 (1 row)
 
 SELECT EXTRACT(CENTURY FROM INTERVAL '-100 y');
- date_part 
------------
-        -1
+ extract 
+---------
+      -1
+(1 row)
+
+-- date_part implementation is mostly the same as extract, so only
+-- test a few cases for additional coverage.
+SELECT f1,
+    date_part('microsecond', f1) AS microsecond,
+    date_part('millisecond', f1) AS millisecond,
+    date_part('second', f1) AS second,
+    date_part('epoch', f1) AS epoch
+    FROM INTERVAL_TBL;
+              f1               | microsecond | millisecond | second |   epoch    
+-------------------------------+-------------+-------------+--------+------------
+ @ 1 min                       |           0 |           0 |      0 |         60
+ @ 5 hours                     |           0 |           0 |      0 |      18000
+ @ 10 days                     |           0 |           0 |      0 |     864000
+ @ 34 years                    |           0 |           0 |      0 | 1072958400
+ @ 3 mons                      |           0 |           0 |      0 |    7776000
+ @ 14 secs ago                 |   -14000000 |      -14000 |    -14 |        -14
+ @ 1 day 2 hours 3 mins 4 secs |     4000000 |        4000 |      4 |      93784
+ @ 6 years                     |           0 |           0 |      0 |  189345600
+ @ 5 mons                      |           0 |           0 |      0 |   12960000
+ @ 5 mons 12 hours             |           0 |           0 |      0 |   13003200
+(10 rows)
+
+-- internal overflow test case
+SELECT extract(epoch from interval '1000000000 days');
+        extract        
+-----------------------
+ 86400000000000.000000
 (1 row)
 
diff --git a/src/test/regress/expected/psql_crosstab.out b/src/test/regress/expected/psql_crosstab.out
index eae6fbd0512..e09e3310165 100644
--- a/src/test/regress/expected/psql_crosstab.out
+++ b/src/test/regress/expected/psql_crosstab.out
@@ -17,12 +17,12 @@ SELECT v, EXTRACT(year FROM d), count(*)
  FROM ctv_data
  GROUP BY 1, 2
  ORDER BY 1, 2;
- v  | date_part | count 
-----+-----------+-------
- v0 |      2014 |     2
- v0 |      2015 |     1
- v1 |      2015 |     3
- v2 |      2015 |     1
+ v  | extract | count 
+----+---------+-------
+ v0 |    2014 |     2
+ v0 |    2015 |     1
+ v1 |    2015 |     3
+ v2 |    2015 |     1
 (4 rows)
 
 -- basic usage with 3 columns
diff --git a/src/test/regress/expected/time.out b/src/test/regress/expected/time.out
index 5303cc0c947..39b409feca9 100644
--- a/src/test/regress/expected/time.out
+++ b/src/test/regress/expected/time.out
@@ -131,33 +131,33 @@ HINT:  Could not choose a best candidate operator. You might need to add explici
 -- test EXTRACT
 --
 SELECT EXTRACT(MICROSECOND FROM TIME '2020-05-26 13:30:25.575401');
- date_part 
------------
-  25575401
+ extract  
+----------
+ 25575401
 (1 row)
 
 SELECT EXTRACT(MILLISECOND FROM TIME '2020-05-26 13:30:25.575401');
- date_part 
+  extract  
 -----------
  25575.401
 (1 row)
 
 SELECT EXTRACT(SECOND      FROM TIME '2020-05-26 13:30:25.575401');
- date_part 
+  extract  
 -----------
  25.575401
 (1 row)
 
 SELECT EXTRACT(MINUTE      FROM TIME '2020-05-26 13:30:25.575401');
- date_part 
------------
-        30
+ extract 
+---------
+      30
 (1 row)
 
 SELECT EXTRACT(HOUR        FROM TIME '2020-05-26 13:30:25.575401');
- date_part 
------------
-        13
+ extract 
+---------
+      13
 (1 row)
 
 SELECT EXTRACT(DAY         FROM TIME '2020-05-26 13:30:25.575401');  -- error
@@ -167,6 +167,32 @@ ERROR:  "time" units "fortnight" not recognized
 SELECT EXTRACT(TIMEZONE    FROM TIME '2020-05-26 13:30:25.575401');  -- error
 ERROR:  "time" units "timezone" not recognized
 SELECT EXTRACT(EPOCH       FROM TIME '2020-05-26 13:30:25.575401');
+   extract    
+--------------
+ 48625.575401
+(1 row)
+
+-- date_part implementation is mostly the same as extract, so only
+-- test a few cases for additional coverage.
+SELECT date_part('microsecond', TIME '2020-05-26 13:30:25.575401');
+ date_part 
+-----------
+  25575401
+(1 row)
+
+SELECT date_part('millisecond', TIME '2020-05-26 13:30:25.575401');
+ date_part 
+-----------
+ 25575.401
+(1 row)
+
+SELECT date_part('second',      TIME '2020-05-26 13:30:25.575401');
+ date_part 
+-----------
+ 25.575401
+(1 row)
+
+SELECT date_part('epoch',       TIME '2020-05-26 13:30:25.575401');
   date_part   
 --------------
  48625.575401
diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
index fff3cf08c17..690656dfb2d 100644
--- a/src/test/regress/expected/timestamp.out
+++ b/src/test/regress/expected/timestamp.out
@@ -1012,6 +1012,84 @@ SELECT d1 as "timestamp",
  Mon Jan 01 17:32:01 2001    |       200 |        21 |          3 |   2451912 |    978370321
 (65 rows)
 
+-- extract implementation is mostly the same as date_part, so only
+-- test a few cases for additional coverage.
+SELECT d1 as "timestamp",
+   extract(microseconds from d1) AS microseconds,
+   extract(milliseconds from d1) AS milliseconds,
+   extract(seconds from d1) AS seconds,
+   round(extract(julian from d1)) AS julian,
+   extract(epoch from d1) AS epoch
+   FROM TIMESTAMP_TBL;
+          timestamp          | microseconds | milliseconds |  seconds  |  julian   |        epoch        
+-----------------------------+--------------+--------------+-----------+-----------+---------------------
+ -infinity                   |              |              |           | -Infinity |           -Infinity
+ infinity                    |              |              |           |  Infinity |            Infinity
+ Thu Jan 01 00:00:00 1970    |            0 |        0.000 |  0.000000 |   2440588 |            0.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:02 1997    |      2000000 |     2000.000 |  2.000000 |   2450491 |    855595922.000000
+ Mon Feb 10 17:32:01.4 1997  |      1400000 |     1400.000 |  1.400000 |   2450491 |    855595921.400000
+ Mon Feb 10 17:32:01.5 1997  |      1500000 |     1500.000 |  1.500000 |   2450491 |    855595921.500000
+ Mon Feb 10 17:32:01.6 1997  |      1600000 |     1600.000 |  1.600000 |   2450491 |    855595921.600000
+ Thu Jan 02 00:00:00 1997    |            0 |        0.000 |  0.000000 |   2450451 |    852163200.000000
+ Thu Jan 02 03:04:05 1997    |      5000000 |     5000.000 |  5.000000 |   2450451 |    852174245.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Tue Jun 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450611 |    865963921.000000
+ Sat Sep 22 18:19:20 2001    |     20000000 |    20000.000 | 20.000000 |   2452176 |   1001182760.000000
+ Wed Mar 15 08:14:01 2000    |      1000000 |     1000.000 |  1.000000 |   2451619 |    953108041.000000
+ Wed Mar 15 13:14:02 2000    |      2000000 |     2000.000 |  2.000000 |   2451620 |    953126042.000000
+ Wed Mar 15 12:14:03 2000    |      3000000 |     3000.000 |  3.000000 |   2451620 |    953122443.000000
+ Wed Mar 15 03:14:04 2000    |      4000000 |     4000.000 |  4.000000 |   2451619 |    953090044.000000
+ Wed Mar 15 02:14:05 2000    |      5000000 |     5000.000 |  5.000000 |   2451619 |    953086445.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:00 1997    |            0 |        0.000 |  0.000000 |   2450491 |    855595920.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Tue Jun 10 18:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450611 |    865967521.000000
+ Mon Feb 10 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855595921.000000
+ Tue Feb 11 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450492 |    855682321.000000
+ Wed Feb 12 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450493 |    855768721.000000
+ Thu Feb 13 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450494 |    855855121.000000
+ Fri Feb 14 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450495 |    855941521.000000
+ Sat Feb 15 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450496 |    856027921.000000
+ Sun Feb 16 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450497 |    856114321.000000
+ Tue Feb 16 17:32:01 0097 BC |      1000000 |     1000.000 |  1.000000 |   1686043 | -65192711279.000000
+ Sat Feb 16 17:32:01 0097    |      1000000 |     1000.000 |  1.000000 |   1756537 | -59102029679.000000
+ Thu Feb 16 17:32:01 0597    |      1000000 |     1000.000 |  1.000000 |   1939158 | -43323575279.000000
+ Tue Feb 16 17:32:01 1097    |      1000000 |     1000.000 |  1.000000 |   2121779 | -27545120879.000000
+ Sat Feb 16 17:32:01 1697    |      1000000 |     1000.000 |  1.000000 |   2340925 |  -8610906479.000000
+ Thu Feb 16 17:32:01 1797    |      1000000 |     1000.000 |  1.000000 |   2377449 |  -5455232879.000000
+ Tue Feb 16 17:32:01 1897    |      1000000 |     1000.000 |  1.000000 |   2413973 |  -2299559279.000000
+ Sun Feb 16 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450497 |    856114321.000000
+ Sat Feb 16 17:32:01 2097    |      1000000 |     1000.000 |  1.000000 |   2487022 |   4011874321.000000
+ Wed Feb 28 17:32:01 1996    |      1000000 |     1000.000 |  1.000000 |   2450143 |    825528721.000000
+ Thu Feb 29 17:32:01 1996    |      1000000 |     1000.000 |  1.000000 |   2450144 |    825615121.000000
+ Fri Mar 01 17:32:01 1996    |      1000000 |     1000.000 |  1.000000 |   2450145 |    825701521.000000
+ Mon Dec 30 17:32:01 1996    |      1000000 |     1000.000 |  1.000000 |   2450449 |    851967121.000000
+ Tue Dec 31 17:32:01 1996    |      1000000 |     1000.000 |  1.000000 |   2450450 |    852053521.000000
+ Wed Jan 01 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450451 |    852139921.000000
+ Fri Feb 28 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450509 |    857151121.000000
+ Sat Mar 01 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450510 |    857237521.000000
+ Tue Dec 30 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450814 |    883503121.000000
+ Wed Dec 31 17:32:01 1997    |      1000000 |     1000.000 |  1.000000 |   2450815 |    883589521.000000
+ Fri Dec 31 17:32:01 1999    |      1000000 |     1000.000 |  1.000000 |   2451545 |    946661521.000000
+ Sat Jan 01 17:32:01 2000    |      1000000 |     1000.000 |  1.000000 |   2451546 |    946747921.000000
+ Sun Dec 31 17:32:01 2000    |      1000000 |     1000.000 |  1.000000 |   2451911 |    978283921.000000
+ Mon Jan 01 17:32:01 2001    |      1000000 |     1000.000 |  1.000000 |   2451912 |    978370321.000000
+(65 rows)
+
 -- value near upper bound uses special case in code
 SELECT date_part('epoch', '294270-01-01 00:00:00'::timestamp);
    date_part   
@@ -1019,6 +1097,19 @@ SELECT date_part('epoch', '294270-01-01 00:00:00'::timestamp);
  9224097091200
 (1 row)
 
+SELECT extract(epoch from '294270-01-01 00:00:00'::timestamp);
+       extract        
+----------------------
+ 9224097091200.000000
+(1 row)
+
+-- another internal overflow test case
+SELECT extract(epoch from '5000-01-01 00:00:00'::timestamp);
+      extract       
+--------------------
+ 95617584000.000000
+(1 row)
+
 -- TO_CHAR()
 SELECT to_char(d1, 'DAY Day day DY Dy dy MONTH Month month RM MON Mon mon')
    FROM TIMESTAMP_TBL;
diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out
index ff070080731..421ef2578ac 100644
--- a/src/test/regress/expected/timestamptz.out
+++ b/src/test/regress/expected/timestamptz.out
@@ -1189,6 +1189,85 @@ SELECT d1 as timestamptz,
  Mon Jan 01 17:32:01 2001 PST    |   -28800 |            -8 |               0
 (66 rows)
 
+-- extract implementation is mostly the same as date_part, so only
+-- test a few cases for additional coverage.
+SELECT d1 as "timestamp",
+   extract(microseconds from d1) AS microseconds,
+   extract(milliseconds from d1) AS milliseconds,
+   extract(seconds from d1) AS seconds,
+   round(extract(julian from d1)) AS julian,
+   extract(epoch from d1) AS epoch
+   FROM TIMESTAMPTZ_TBL;
+            timestamp            | microseconds | milliseconds |  seconds  |  julian   |        epoch        
+---------------------------------+--------------+--------------+-----------+-----------+---------------------
+ -infinity                       |              |              |           | -Infinity |           -Infinity
+ infinity                        |              |              |           |  Infinity |            Infinity
+ Wed Dec 31 16:00:00 1969 PST    |            0 |        0.000 |  0.000000 |   2440588 |            0.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:02 1997 PST    |      2000000 |     2000.000 |  2.000000 |   2450491 |    855624722.000000
+ Mon Feb 10 17:32:01.4 1997 PST  |      1400000 |     1400.000 |  1.400000 |   2450491 |    855624721.400000
+ Mon Feb 10 17:32:01.5 1997 PST  |      1500000 |     1500.000 |  1.500000 |   2450491 |    855624721.500000
+ Mon Feb 10 17:32:01.6 1997 PST  |      1600000 |     1600.000 |  1.600000 |   2450491 |    855624721.600000
+ Thu Jan 02 00:00:00 1997 PST    |            0 |        0.000 |  0.000000 |   2450451 |    852192000.000000
+ Thu Jan 02 03:04:05 1997 PST    |      5000000 |     5000.000 |  5.000000 |   2450451 |    852203045.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Tue Jun 10 17:32:01 1997 PDT    |      1000000 |     1000.000 |  1.000000 |   2450611 |    865989121.000000
+ Sat Sep 22 18:19:20 2001 PDT    |     20000000 |    20000.000 | 20.000000 |   2452176 |   1001207960.000000
+ Wed Mar 15 08:14:01 2000 PST    |      1000000 |     1000.000 |  1.000000 |   2451619 |    953136841.000000
+ Wed Mar 15 04:14:02 2000 PST    |      2000000 |     2000.000 |  2.000000 |   2451619 |    953122442.000000
+ Wed Mar 15 02:14:03 2000 PST    |      3000000 |     3000.000 |  3.000000 |   2451619 |    953115243.000000
+ Wed Mar 15 03:14:04 2000 PST    |      4000000 |     4000.000 |  4.000000 |   2451619 |    953118844.000000
+ Wed Mar 15 01:14:05 2000 PST    |      5000000 |     5000.000 |  5.000000 |   2451619 |    953111645.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:00 1997 PST    |            0 |        0.000 |  0.000000 |   2450491 |    855624720.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Mon Feb 10 09:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450490 |    855595921.000000
+ Mon Feb 10 09:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450490 |    855595921.000000
+ Mon Feb 10 09:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450490 |    855595921.000000
+ Mon Feb 10 14:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855613921.000000
+ Thu Jul 10 14:32:01 1997 PDT    |      1000000 |     1000.000 |  1.000000 |   2450641 |    868570321.000000
+ Tue Jun 10 18:32:01 1997 PDT    |      1000000 |     1000.000 |  1.000000 |   2450611 |    865992721.000000
+ Mon Feb 10 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450491 |    855624721.000000
+ Tue Feb 11 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450492 |    855711121.000000
+ Wed Feb 12 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450493 |    855797521.000000
+ Thu Feb 13 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450494 |    855883921.000000
+ Fri Feb 14 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450495 |    855970321.000000
+ Sat Feb 15 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450496 |    856056721.000000
+ Sun Feb 16 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450497 |    856143121.000000
+ Tue Feb 16 17:32:01 0097 PST BC |      1000000 |     1000.000 |  1.000000 |   1686043 | -65192682479.000000
+ Sat Feb 16 17:32:01 0097 PST    |      1000000 |     1000.000 |  1.000000 |   1756537 | -59102000879.000000
+ Thu Feb 16 17:32:01 0597 PST    |      1000000 |     1000.000 |  1.000000 |   1939158 | -43323546479.000000
+ Tue Feb 16 17:32:01 1097 PST    |      1000000 |     1000.000 |  1.000000 |   2121779 | -27545092079.000000
+ Sat Feb 16 17:32:01 1697 PST    |      1000000 |     1000.000 |  1.000000 |   2340925 |  -8610877679.000000
+ Thu Feb 16 17:32:01 1797 PST    |      1000000 |     1000.000 |  1.000000 |   2377449 |  -5455204079.000000
+ Tue Feb 16 17:32:01 1897 PST    |      1000000 |     1000.000 |  1.000000 |   2413973 |  -2299530479.000000
+ Sun Feb 16 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450497 |    856143121.000000
+ Sat Feb 16 17:32:01 2097 PST    |      1000000 |     1000.000 |  1.000000 |   2487022 |   4011903121.000000
+ Wed Feb 28 17:32:01 1996 PST    |      1000000 |     1000.000 |  1.000000 |   2450143 |    825557521.000000
+ Thu Feb 29 17:32:01 1996 PST    |      1000000 |     1000.000 |  1.000000 |   2450144 |    825643921.000000
+ Fri Mar 01 17:32:01 1996 PST    |      1000000 |     1000.000 |  1.000000 |   2450145 |    825730321.000000
+ Mon Dec 30 17:32:01 1996 PST    |      1000000 |     1000.000 |  1.000000 |   2450449 |    851995921.000000
+ Tue Dec 31 17:32:01 1996 PST    |      1000000 |     1000.000 |  1.000000 |   2450450 |    852082321.000000
+ Wed Jan 01 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450451 |    852168721.000000
+ Fri Feb 28 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450509 |    857179921.000000
+ Sat Mar 01 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450510 |    857266321.000000
+ Tue Dec 30 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450814 |    883531921.000000
+ Wed Dec 31 17:32:01 1997 PST    |      1000000 |     1000.000 |  1.000000 |   2450815 |    883618321.000000
+ Fri Dec 31 17:32:01 1999 PST    |      1000000 |     1000.000 |  1.000000 |   2451545 |    946690321.000000
+ Sat Jan 01 17:32:01 2000 PST    |      1000000 |     1000.000 |  1.000000 |   2451546 |    946776721.000000
+ Sun Dec 31 17:32:01 2000 PST    |      1000000 |     1000.000 |  1.000000 |   2451911 |    978312721.000000
+ Mon Jan 01 17:32:01 2001 PST    |      1000000 |     1000.000 |  1.000000 |   2451912 |    978399121.000000
+(66 rows)
+
 -- value near upper bound uses special case in code
 SELECT date_part('epoch', '294270-01-01 00:00:00+00'::timestamptz);
    date_part   
@@ -1196,6 +1275,19 @@ SELECT date_part('epoch', '294270-01-01 00:00:00+00'::timestamptz);
  9224097091200
 (1 row)
 
+SELECT extract(epoch from '294270-01-01 00:00:00+00'::timestamptz);
+       extract        
+----------------------
+ 9224097091200.000000
+(1 row)
+
+-- another internal overflow test case
+SELECT extract(epoch from '5000-01-01 00:00:00+00'::timestamptz);
+      extract       
+--------------------
+ 95617584000.000000
+(1 row)
+
 -- TO_CHAR()
 SELECT to_char(d1, 'DAY Day day DY Dy dy MONTH Month month RM MON Mon mon')
    FROM TIMESTAMPTZ_TBL;
diff --git a/src/test/regress/expected/timetz.out b/src/test/regress/expected/timetz.out
index 0ae5b5204d6..f4960c0166d 100644
--- a/src/test/regress/expected/timetz.out
+++ b/src/test/regress/expected/timetz.out
@@ -148,33 +148,33 @@ HINT:  No operator matches the given name and argument types. You might need to
 -- test EXTRACT
 --
 SELECT EXTRACT(MICROSECOND FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
- date_part 
------------
-  25575401
+ extract  
+----------
+ 25575401
 (1 row)
 
 SELECT EXTRACT(MILLISECOND FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
- date_part 
+  extract  
 -----------
  25575.401
 (1 row)
 
 SELECT EXTRACT(SECOND      FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
- date_part 
+  extract  
 -----------
  25.575401
 (1 row)
 
 SELECT EXTRACT(MINUTE      FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
- date_part 
------------
-        30
+ extract 
+---------
+      30
 (1 row)
 
 SELECT EXTRACT(HOUR        FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
- date_part 
------------
-        13
+ extract 
+---------
+      13
 (1 row)
 
 SELECT EXTRACT(DAY         FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');  -- error
@@ -182,24 +182,50 @@ ERROR:  "time with time zone" units "day" not recognized
 SELECT EXTRACT(FORTNIGHT   FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');  -- error
 ERROR:  "time with time zone" units "fortnight" not recognized
 SELECT EXTRACT(TIMEZONE    FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04:30');
+ extract 
+---------
+  -16200
+(1 row)
+
+SELECT EXTRACT(TIMEZONE_HOUR   FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04:30');
+ extract 
+---------
+      -4
+(1 row)
+
+SELECT EXTRACT(TIMEZONE_MINUTE FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04:30');
+ extract 
+---------
+     -30
+(1 row)
+
+SELECT EXTRACT(EPOCH       FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
+   extract    
+--------------
+ 63025.575401
+(1 row)
+
+-- date_part implementation is mostly the same as extract, so only
+-- test a few cases for additional coverage.
+SELECT date_part('microsecond', TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
  date_part 
 -----------
-    -16200
+  25575401
 (1 row)
 
-SELECT EXTRACT(TIMEZONE_HOUR   FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04:30');
+SELECT date_part('millisecond', TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
  date_part 
 -----------
-        -4
+ 25575.401
 (1 row)
 
-SELECT EXTRACT(TIMEZONE_MINUTE FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04:30');
+SELECT date_part('second',      TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
  date_part 
 -----------
-       -30
+ 25.575401
 (1 row)
 
-SELECT EXTRACT(EPOCH       FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
+SELECT date_part('epoch',       TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
   date_part   
 --------------
  63025.575401
diff --git a/src/test/regress/sql/date.sql b/src/test/regress/sql/date.sql
index 1cdd6bdca12..8f7435b767c 100644
--- a/src/test/regress/sql/date.sql
+++ b/src/test/regress/sql/date.sql
@@ -284,14 +284,18 @@ SELECT EXTRACT(HOUR          FROM DATE '2020-08-11');
 SELECT EXTRACT(DAY           FROM DATE '2020-08-11');
 SELECT EXTRACT(MONTH         FROM DATE '2020-08-11');
 SELECT EXTRACT(YEAR          FROM DATE '2020-08-11');
+SELECT EXTRACT(YEAR          FROM DATE '2020-08-11 BC');
 SELECT EXTRACT(DECADE        FROM DATE '2020-08-11');
 SELECT EXTRACT(CENTURY       FROM DATE '2020-08-11');
 SELECT EXTRACT(MILLENNIUM    FROM DATE '2020-08-11');
 SELECT EXTRACT(ISOYEAR       FROM DATE '2020-08-11');
+SELECT EXTRACT(ISOYEAR       FROM DATE '2020-08-11 BC');
 SELECT EXTRACT(QUARTER       FROM DATE '2020-08-11');
 SELECT EXTRACT(WEEK          FROM DATE '2020-08-11');
 SELECT EXTRACT(DOW           FROM DATE '2020-08-11');
+SELECT EXTRACT(DOW           FROM DATE '2020-08-16');
 SELECT EXTRACT(ISODOW        FROM DATE '2020-08-11');
+SELECT EXTRACT(ISODOW        FROM DATE '2020-08-16');
 SELECT EXTRACT(DOY           FROM DATE '2020-08-11');
 SELECT EXTRACT(TIMEZONE      FROM DATE '2020-08-11');
 SELECT EXTRACT(TIMEZONE_M    FROM DATE '2020-08-11');
@@ -321,14 +325,9 @@ select isfinite('infinity'::date), isfinite('-infinity'::date), isfinite('today'
 --
 -- oscillating fields from non-finite date:
 --
-SELECT EXTRACT(HOUR FROM DATE 'infinity');      -- NULL
-SELECT EXTRACT(HOUR FROM DATE '-infinity');     -- NULL
--- all possible fields
-SELECT EXTRACT(MICROSECONDS  FROM DATE 'infinity');    -- NULL
-SELECT EXTRACT(MILLISECONDS  FROM DATE 'infinity');    -- NULL
-SELECT EXTRACT(SECOND        FROM DATE 'infinity');    -- NULL
-SELECT EXTRACT(MINUTE        FROM DATE 'infinity');    -- NULL
-SELECT EXTRACT(HOUR          FROM DATE 'infinity');    -- NULL
+SELECT EXTRACT(DAY FROM DATE 'infinity');      -- NULL
+SELECT EXTRACT(DAY FROM DATE '-infinity');     -- NULL
+-- all supported fields
 SELECT EXTRACT(DAY           FROM DATE 'infinity');    -- NULL
 SELECT EXTRACT(MONTH         FROM DATE 'infinity');    -- NULL
 SELECT EXTRACT(QUARTER       FROM DATE 'infinity');    -- NULL
@@ -336,15 +335,12 @@ SELECT EXTRACT(WEEK          FROM DATE 'infinity');    -- NULL
 SELECT EXTRACT(DOW           FROM DATE 'infinity');    -- NULL
 SELECT EXTRACT(ISODOW        FROM DATE 'infinity');    -- NULL
 SELECT EXTRACT(DOY           FROM DATE 'infinity');    -- NULL
-SELECT EXTRACT(TIMEZONE      FROM DATE 'infinity');    -- NULL
-SELECT EXTRACT(TIMEZONE_M    FROM DATE 'infinity');    -- NULL
-SELECT EXTRACT(TIMEZONE_H    FROM DATE 'infinity');    -- NULL
 --
 -- monotonic fields from non-finite date:
 --
 SELECT EXTRACT(EPOCH FROM DATE 'infinity');         --  Infinity
 SELECT EXTRACT(EPOCH FROM DATE '-infinity');        -- -Infinity
--- all possible fields
+-- all supported fields
 SELECT EXTRACT(YEAR       FROM DATE 'infinity');    --  Infinity
 SELECT EXTRACT(DECADE     FROM DATE 'infinity');    --  Infinity
 SELECT EXTRACT(CENTURY    FROM DATE 'infinity');    --  Infinity
@@ -355,7 +351,7 @@ SELECT EXTRACT(EPOCH      FROM DATE 'infinity');    --  Infinity
 --
 -- wrong fields from non-finite date:
 --
-SELECT EXTRACT(MICROSEC  FROM DATE 'infinity');     -- ERROR:  timestamp units "microsec" not recognized
+SELECT EXTRACT(MICROSEC  FROM DATE 'infinity');     -- error
 
 -- test constructors
 select make_date(2013, 7, 15);
diff --git a/src/test/regress/sql/interval.sql b/src/test/regress/sql/interval.sql
index 11c1929bef5..6d532398bd6 100644
--- a/src/test/regress/sql/interval.sql
+++ b/src/test/regress/sql/interval.sql
@@ -343,3 +343,15 @@ SELECT EXTRACT(CENTURY FROM INTERVAL '100 y');
 SELECT EXTRACT(CENTURY FROM INTERVAL '99 y');
 SELECT EXTRACT(CENTURY FROM INTERVAL '-99 y');
 SELECT EXTRACT(CENTURY FROM INTERVAL '-100 y');
+
+-- date_part implementation is mostly the same as extract, so only
+-- test a few cases for additional coverage.
+SELECT f1,
+    date_part('microsecond', f1) AS microsecond,
+    date_part('millisecond', f1) AS millisecond,
+    date_part('second', f1) AS second,
+    date_part('epoch', f1) AS epoch
+    FROM INTERVAL_TBL;
+
+-- internal overflow test case
+SELECT extract(epoch from interval '1000000000 days');
diff --git a/src/test/regress/sql/time.sql b/src/test/regress/sql/time.sql
index 688bd6b75ba..3637f28798b 100644
--- a/src/test/regress/sql/time.sql
+++ b/src/test/regress/sql/time.sql
@@ -63,3 +63,10 @@ SELECT EXTRACT(DAY         FROM TIME '2020-05-26 13:30:25.575401');  -- error
 SELECT EXTRACT(FORTNIGHT   FROM TIME '2020-05-26 13:30:25.575401');  -- error
 SELECT EXTRACT(TIMEZONE    FROM TIME '2020-05-26 13:30:25.575401');  -- error
 SELECT EXTRACT(EPOCH       FROM TIME '2020-05-26 13:30:25.575401');
+
+-- date_part implementation is mostly the same as extract, so only
+-- test a few cases for additional coverage.
+SELECT date_part('microsecond', TIME '2020-05-26 13:30:25.575401');
+SELECT date_part('millisecond', TIME '2020-05-26 13:30:25.575401');
+SELECT date_part('second',      TIME '2020-05-26 13:30:25.575401');
+SELECT date_part('epoch',       TIME '2020-05-26 13:30:25.575401');
diff --git a/src/test/regress/sql/timestamp.sql b/src/test/regress/sql/timestamp.sql
index ed03d7c2187..c43a1f22688 100644
--- a/src/test/regress/sql/timestamp.sql
+++ b/src/test/regress/sql/timestamp.sql
@@ -261,8 +261,21 @@ SELECT d1 as "timestamp",
    date_part( 'epoch', d1) AS epoch
    FROM TIMESTAMP_TBL;
 
+-- extract implementation is mostly the same as date_part, so only
+-- test a few cases for additional coverage.
+SELECT d1 as "timestamp",
+   extract(microseconds from d1) AS microseconds,
+   extract(milliseconds from d1) AS milliseconds,
+   extract(seconds from d1) AS seconds,
+   round(extract(julian from d1)) AS julian,
+   extract(epoch from d1) AS epoch
+   FROM TIMESTAMP_TBL;
+
 -- value near upper bound uses special case in code
 SELECT date_part('epoch', '294270-01-01 00:00:00'::timestamp);
+SELECT extract(epoch from '294270-01-01 00:00:00'::timestamp);
+-- another internal overflow test case
+SELECT extract(epoch from '5000-01-01 00:00:00'::timestamp);
 
 -- TO_CHAR()
 SELECT to_char(d1, 'DAY Day day DY Dy dy MONTH Month month RM MON Mon mon')
diff --git a/src/test/regress/sql/timestamptz.sql b/src/test/regress/sql/timestamptz.sql
index fd1bf50a9c1..17ced99efca 100644
--- a/src/test/regress/sql/timestamptz.sql
+++ b/src/test/regress/sql/timestamptz.sql
@@ -275,8 +275,21 @@ SELECT d1 as timestamptz,
    date_part( 'timezone_minute', d1) AS timezone_minute
    FROM TIMESTAMPTZ_TBL;
 
+-- extract implementation is mostly the same as date_part, so only
+-- test a few cases for additional coverage.
+SELECT d1 as "timestamp",
+   extract(microseconds from d1) AS microseconds,
+   extract(milliseconds from d1) AS milliseconds,
+   extract(seconds from d1) AS seconds,
+   round(extract(julian from d1)) AS julian,
+   extract(epoch from d1) AS epoch
+   FROM TIMESTAMPTZ_TBL;
+
 -- value near upper bound uses special case in code
 SELECT date_part('epoch', '294270-01-01 00:00:00+00'::timestamptz);
+SELECT extract(epoch from '294270-01-01 00:00:00+00'::timestamptz);
+-- another internal overflow test case
+SELECT extract(epoch from '5000-01-01 00:00:00+00'::timestamptz);
 
 -- TO_CHAR()
 SELECT to_char(d1, 'DAY Day day DY Dy dy MONTH Month month RM MON Mon mon')
diff --git a/src/test/regress/sql/timetz.sql b/src/test/regress/sql/timetz.sql
index f39ea121bf7..7b70f4656c9 100644
--- a/src/test/regress/sql/timetz.sql
+++ b/src/test/regress/sql/timetz.sql
@@ -70,3 +70,10 @@ SELECT EXTRACT(TIMEZONE    FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-
 SELECT EXTRACT(TIMEZONE_HOUR   FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04:30');
 SELECT EXTRACT(TIMEZONE_MINUTE FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04:30');
 SELECT EXTRACT(EPOCH       FROM TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
+
+-- date_part implementation is mostly the same as extract, so only
+-- test a few cases for additional coverage.
+SELECT date_part('microsecond', TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
+SELECT date_part('millisecond', TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
+SELECT date_part('second',      TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');
+SELECT date_part('epoch',       TIME WITH TIME ZONE '2020-05-26 13:30:25.575401-04');