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
40c24bfe.

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 <petr.fedorov@phystech.edu>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/42b73d2d-da12-ba9f-570a-420e0cce19d9@phystech.edu

doc/src/sgml/func.sgml

@@ -8872,7 +8872,7 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
           <primary>extract</primary>
          </indexterm>
          <function>extract</function> ( <parameter>field</parameter> <literal>from</literal> <type>timestamp</type> )
-         <returnvalue>double precision</returnvalue>
+         <returnvalue>numeric</returnvalue>
         </para>
         <para>
          Get timestamp subfield; see <xref linkend="functions-datetime-extract"/>
@@ -8886,7 +8886,7 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        <row>
         <entry role="func_table_entry"><para role="func_signature">
          <function>extract</function> ( <parameter>field</parameter> <literal>from</literal> <type>interval</type> )
-         <returnvalue>double precision</returnvalue>
+         <returnvalue>numeric</returnvalue>
         </para>
         <para>
          Get interval subfield; see <xref linkend="functions-datetime-extract"/>
@@ -9401,7 +9401,7 @@ EXTRACT(<replaceable>field</replaceable> FROM <replaceable>source</replaceable>)
     well.)  <replaceable>field</replaceable> is an identifier or
     string that selects what field to extract from the source value.
     The <function>extract</function> function returns values of type
-    <type>double precision</type>.
+    <type>numeric</type>.
     The following are valid field names:
 
     <!-- alphabetical -->
@@ -9825,6 +9825,10 @@ date_part('<replaceable>field</replaceable>', <replaceable>source</replaceable>)
     be a string value, not a name.  The valid field names for
     <function>date_part</function> are the same as for
     <function>extract</function>.
+    For historical reasons, the <function>date_part</function> function
+    returns values of type <type>double precision</type>.  This can result in
+    a loss of precision in certain uses.  Using <function>extract</function>
+    is recommended instead.
    </para>
 
 <screen>

src/backend/parser/gram.y

@@ -14020,7 +14020,7 @@ func_expr_common_subexpr:
 				{ $$ = makeTypeCast($3, $5, @1); }
 			| EXTRACT '(' extract_list ')'
 				{
-					$$ = (Node *) makeFuncCall(SystemFuncName("date_part"),
+					$$ = (Node *) makeFuncCall(SystemFuncName("extract"),
 											   $3,
 											   COERCE_SQL_SYNTAX,
 											   @1);

src/backend/utils/adt/numeric.c

@@ -4092,6 +4092,67 @@ int64_to_numeric(int64 val)
 	return res;
 }
 
+/*
+ * Convert val1/(10**val2) to numeric.  This is much faster than normal
+ * numeric division.
+ */
+Numeric
+int64_div_fast_to_numeric(int64 val1, int log10val2)
+{
+	Numeric		res;
+	NumericVar	result;
+	int64		saved_val1 = val1;
+	int			w;
+	int			m;
+
+	/* how much to decrease the weight by */
+	w = log10val2 / DEC_DIGITS;
+	/* how much is left */
+	m = log10val2 % DEC_DIGITS;
+
+	/*
+	 * If there is anything left, multiply the dividend by what's left, then
+	 * shift the weight by one more.
+	 */
+	if (m > 0)
+	{
+		static int	pow10[] = {1, 10, 100, 1000};
+
+		StaticAssertStmt(lengthof(pow10) == DEC_DIGITS, "mismatch with DEC_DIGITS");
+		if (unlikely(pg_mul_s64_overflow(val1, pow10[DEC_DIGITS - m], &val1)))
+		{
+			/*
+			 * If it doesn't fit, do the whole computation in numeric the slow
+			 * way.  Note that va1l may have been overwritten, so use
+			 * saved_val1 instead.
+			 */
+			int			val2 = 1;
+
+			for (int i = 0; i < log10val2; i++)
+				val2 *= 10;
+			res = numeric_div_opt_error(int64_to_numeric(saved_val1), int64_to_numeric(val2), NULL);
+			res = DatumGetNumeric(DirectFunctionCall2(numeric_round,
+													  NumericGetDatum(res),
+													  Int32GetDatum(log10val2)));
+			return res;
+		}
+		w++;
+	}
+
+	init_var(&result);
+
+	int64_to_numericvar(val1, &result);
+
+	result.weight -= w;
+	result.dscale += w * DEC_DIGITS - (DEC_DIGITS - m);
+
+	res = make_result(&result);
+
+	free_var(&result);
+
+	return res;
+}
+
 Datum
 int4_numeric(PG_FUNCTION_ARGS)
 {

src/backend/utils/adt/ruleutils.c

@@ -9782,6 +9782,27 @@ get_func_sql_syntax(FuncExpr *expr, deparse_context *context)
 			appendStringInfoString(buf, "))");
 			return true;
 
+		case F_EXTRACT_TEXT_DATE:
+		case F_EXTRACT_TEXT_TIME:
+		case F_EXTRACT_TEXT_TIMETZ:
+		case F_EXTRACT_TEXT_TIMESTAMP:
+		case F_EXTRACT_TEXT_TIMESTAMPTZ:
+		case F_EXTRACT_TEXT_INTERVAL:
+			/* EXTRACT (x FROM y) */
+			appendStringInfoString(buf, "EXTRACT(");
+			{
+				Const	   *con = (Const *) linitial(expr->args);
+
+				Assert(IsA(con, Const) &&
+					   con->consttype == TEXTOID &&
+					   !con->constisnull);
+				appendStringInfoString(buf, TextDatumGetCString(con->constvalue));
+			}
+			appendStringInfoString(buf, " FROM ");
+			get_rule_expr((Node *) lsecond(expr->args), context, false);
+			appendStringInfoChar(buf, ')');
+			return true;
+
 		case F_IS_NORMALIZED:
 			/* IS xxx NORMALIZED */
 			appendStringInfoString(buf, "((");

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202104061
+#define CATALOG_VERSION_NO	202104062
 
 #endif

src/include/catalog/pg_proc.dat

@@ -2339,9 +2339,15 @@
 { oid => '1171', descr => 'extract field from timestamp with time zone',
   proname => 'date_part', provolatile => 's', prorettype => 'float8',
   proargtypes => 'text timestamptz', prosrc => 'timestamptz_part' },
+{ oid => '9983', descr => 'extract field from timestamp with time zone',
+  proname => 'extract', provolatile => 's', prorettype => 'numeric',
+  proargtypes => 'text timestamptz', prosrc => 'extract_timestamptz' },
 { oid => '1172', descr => 'extract field from interval',
   proname => 'date_part', prorettype => 'float8',
   proargtypes => 'text interval', prosrc => 'interval_part' },
+{ oid => '9984', descr => 'extract field from interval',
+  proname => 'extract', prorettype => 'numeric', proargtypes => 'text interval',
+  prosrc => 'extract_interval' },
 { oid => '1174', descr => 'convert date to timestamp with time zone',
   proname => 'timestamptz', provolatile => 's', prorettype => 'timestamptz',
   proargtypes => 'date', prosrc => 'date_timestamptz' },
@@ -2489,6 +2495,9 @@
 { oid => '1273', descr => 'extract field from time with time zone',
   proname => 'date_part', prorettype => 'float8', proargtypes => 'text timetz',
   prosrc => 'timetz_part' },
+{ oid => '9981', descr => 'extract field from time with time zone',
+  proname => 'extract', prorettype => 'numeric', proargtypes => 'text timetz',
+  prosrc => 'extract_timetz' },
 { oid => '1274',
   proname => 'int84pl', prorettype => 'int8', proargtypes => 'int8 int4',
   prosrc => 'int84pl' },
@@ -2834,9 +2843,15 @@
   proname => 'date_part', prolang => 'sql', prorettype => 'float8',
   proargtypes => 'text date',
   prosrc => 'select pg_catalog.date_part($1, cast($2 as timestamp without time zone))' },
+{ oid => '9979', descr => 'extract field from date',
+  proname => 'extract', prorettype => 'numeric', proargtypes => 'text date',
+  prosrc => 'extract_date' },
 { oid => '1385', descr => 'extract field from time',
   proname => 'date_part', prorettype => 'float8', proargtypes => 'text time',
   prosrc => 'time_part' },
+{ oid => '9980', descr => 'extract field from time',
+  proname => 'extract', prorettype => 'numeric', proargtypes => 'text time',
+  prosrc => 'extract_time' },
 { oid => '1386',
   descr => 'date difference from today preserving months and years',
   proname => 'age', prolang => 'sql', provolatile => 's',
@@ -5835,6 +5850,9 @@
 { oid => '2021', descr => 'extract field from timestamp',
   proname => 'date_part', prorettype => 'float8',
   proargtypes => 'text timestamp', prosrc => 'timestamp_part' },
+{ oid => '9982', descr => 'extract field from timestamp',
+  proname => 'extract', prorettype => 'numeric',
+  proargtypes => 'text timestamp', prosrc => 'extract_timestamp' },
 { oid => '2024', descr => 'convert date to timestamp',
   proname => 'timestamp', prorettype => 'timestamp', proargtypes => 'date',
   prosrc => 'date_timestamp' },

src/include/utils/numeric.h

@@ -63,6 +63,7 @@ extern char *numeric_out_sci(Numeric num, int scale);
 extern char *numeric_normalize(Numeric num);
 
 extern Numeric int64_to_numeric(int64 val);
+extern Numeric int64_div_fast_to_numeric(int64 val1, int log10val2);
 
 extern Numeric numeric_add_opt_error(Numeric num1, Numeric num2,
 									 bool *have_error);

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,                                              +

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)
 

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

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

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;

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;

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

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 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);

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');

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');

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')

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')

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');