diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 0e3d3e8c725..e1e05e4df2c 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -3084,7 +3084,7 @@ DCH_from_char(FormatNode *node, const char *in, TmFromChar *out)
 			case DCH_DY:
 			case DCH_Dy:
 			case DCH_dy:
-				from_char_seq_search(&value, &s, days,
+				from_char_seq_search(&value, &s, days_short,
 									 n);
 				from_char_set_int(&out->d, value, n);
 				out->d++;
@@ -3183,10 +3183,6 @@ DCH_from_char(FormatNode *node, const char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 			case DCH_RM:
-				from_char_seq_search(&value, &s, rm_months_upper,
-									 n);
-				from_char_set_int(&out->mm, MONTHS_PER_YEAR - value, n);
-				break;
 			case DCH_rm:
 				from_char_seq_search(&value, &s, rm_months_lower,
 									 n);
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index b691e307036..dc3a188c51b 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -2822,6 +2822,18 @@ SELECT to_timestamp('20000-1116', 'YYYY-MMDD');
  Thu Nov 16 00:00:00 20000 PST
 (1 row)
 
+SELECT to_timestamp('1997 A.D. 11 16', 'YYYY B.C. MM DD');
+         to_timestamp         
+------------------------------
+ Sun Nov 16 00:00:00 1997 PST
+(1 row)
+
+SELECT to_timestamp('1997 B.C. 11 16', 'YYYY B.C. MM DD');
+          to_timestamp           
+---------------------------------
+ Tue Nov 16 00:00:00 1997 PST BC
+(1 row)
+
 SELECT to_timestamp('9-1116', 'Y-MMDD');
          to_timestamp         
 ------------------------------
@@ -2906,6 +2918,44 @@ SELECT to_timestamp('  20050302', 'YYYYMMDD');
  Wed Mar 02 00:00:00 2005 PST
 (1 row)
 
+SELECT to_timestamp('2011-12-18 11:38 A.M.', 'YYYY-MM-DD HH12:MI P.M.');
+         to_timestamp         
+------------------------------
+ Sun Dec 18 11:38:00 2011 PST
+(1 row)
+
+SELECT to_timestamp('2011-12-18 11:38 P.M.', 'YYYY-MM-DD HH12:MI P.M.');
+         to_timestamp         
+------------------------------
+ Sun Dec 18 23:38:00 2011 PST
+(1 row)
+
+SELECT to_timestamp('2011-12-18 11:38 PST', 'YYYY-MM-DD HH12:MI TZ');  -- NYI
+ERROR:  "TZ"/"tz"/"OF" format patterns are not supported in to_date
+SELECT to_timestamp('2018-11-02 12:34:56.025', 'YYYY-MM-DD HH24:MI:SS.MS');
+           to_timestamp           
+----------------------------------
+ Fri Nov 02 12:34:56.025 2018 PDT
+(1 row)
+
+SELECT to_date('1 4 1902', 'Q MM YYYY');  -- Q is ignored
+  to_date   
+------------
+ 04-01-1902
+(1 row)
+
+SELECT to_date('3 4 21 01', 'W MM CC YY');
+  to_date   
+------------
+ 04-15-2001
+(1 row)
+
+SELECT to_date('2458872', 'J');
+  to_date   
+------------
+ 01-23-2020
+(1 row)
+
 --
 -- Check handling of multiple spaces in format and/or input
 --
@@ -2998,6 +3048,19 @@ SELECT to_timestamp('19971)24', 'YYYYMMDD');
 ERROR:  invalid value "1)" for "MM"
 DETAIL:  Field requires 2 characters, but only 1 could be parsed.
 HINT:  If your source string is not fixed-width, try using the "FM" modifier.
+-- We don't accept full-length day or month names if short form is specified:
+SELECT to_timestamp('Friday 1-January-1999', 'DY DD MON YYYY');
+ERROR:  invalid value "ay" for "DD"
+DETAIL:  Value must be an integer.
+SELECT to_timestamp('Fri 1-January-1999', 'DY DD MON YYYY');
+ERROR:  invalid value "ary-" for "YYYY"
+DETAIL:  Value must be an integer.
+SELECT to_timestamp('Fri 1-Jan-1999', 'DY DD MON YYYY');  -- ok
+         to_timestamp         
+------------------------------
+ Fri Jan 01 00:00:00 1999 PST
+(1 row)
+
 -- Value clobbering:
 SELECT to_timestamp('1997-11-Jan-16', 'YYYY-MM-Mon-DD');
 ERROR:  conflicting values for "Mon" field in formatting string
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index 472d2af794b..5a278e499b0 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -412,6 +412,9 @@ SELECT to_timestamp('19971116', 'YYYYMMDD');
 
 SELECT to_timestamp('20000-1116', 'YYYY-MMDD');
 
+SELECT to_timestamp('1997 A.D. 11 16', 'YYYY B.C. MM DD');
+SELECT to_timestamp('1997 B.C. 11 16', 'YYYY B.C. MM DD');
+
 SELECT to_timestamp('9-1116', 'Y-MMDD');
 
 SELECT to_timestamp('95-1116', 'YY-MMDD');
@@ -440,6 +443,17 @@ SELECT to_timestamp(' 2005 03 02', 'YYYYMMDD');
 
 SELECT to_timestamp('  20050302', 'YYYYMMDD');
 
+SELECT to_timestamp('2011-12-18 11:38 A.M.', 'YYYY-MM-DD HH12:MI P.M.');
+SELECT to_timestamp('2011-12-18 11:38 P.M.', 'YYYY-MM-DD HH12:MI P.M.');
+
+SELECT to_timestamp('2011-12-18 11:38 PST', 'YYYY-MM-DD HH12:MI TZ');  -- NYI
+
+SELECT to_timestamp('2018-11-02 12:34:56.025', 'YYYY-MM-DD HH24:MI:SS.MS');
+
+SELECT to_date('1 4 1902', 'Q MM YYYY');  -- Q is ignored
+SELECT to_date('3 4 21 01', 'W MM CC YY');
+SELECT to_date('2458872', 'J');
+
 --
 -- Check handling of multiple spaces in format and/or input
 --
@@ -473,6 +487,11 @@ SELECT to_timestamp('19971', 'YYYYMMDD');
 -- Insufficient digit characters for a single node:
 SELECT to_timestamp('19971)24', 'YYYYMMDD');
 
+-- We don't accept full-length day or month names if short form is specified:
+SELECT to_timestamp('Friday 1-January-1999', 'DY DD MON YYYY');
+SELECT to_timestamp('Fri 1-January-1999', 'DY DD MON YYYY');
+SELECT to_timestamp('Fri 1-Jan-1999', 'DY DD MON YYYY');  -- ok
+
 -- Value clobbering:
 SELECT to_timestamp('1997-11-Jan-16', 'YYYY-MM-Mon-DD');